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UNIVERSITY  OF  CALIFORNIA. 


GIFT  OF 


DANIEL    C.     OILMAN. 


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ECCE    CCELUM; 


PARISH  ASTRONOMY. 


in  SKx 


BY  A   CONNECTICUT   PASTOR. 


BOSTON: 

NICHOLS  &  NO  YES,  117  WASHINGTON  STREET. 
1869. 


<U 


Entered,  according  to  Act  of  Congress,  in  the  year  1867,  by 

NICHOLS  &  NOYES, 
In  the  Clerk's  Office  of  the  District  Court  of  the  District  of  Massachusetta 


BOSTON:  COKNHILL  PRESS. 

STIBEOTYPED  AND    FEINTED  BT  OEO.  C.  RAND  ft  AVKET. 


fa 

REV.  W.  A.  STEARNS,  D.D.,  LL.D., 

PRESIDENT  OF  AMHERST  COLLEGE, 


OF    PARISH    LECTURES    ON    ASTRONOMY    IN    THE    INTEREST 
OF  RELIGION, 

IS    RESPECTFULLY    DEDICATED 


THE    A  UTHOR. 


A    REMARKABLE    BOOK. 


ECCE    CCELUM; 

OR, 

PARISH    ASTRONOMY. 

BY  REV.  E.  F.  BURR,  D.D. 

1  vol.  16mo,  198  pp.    Price,  $1.25.    New  Edition.    Sent  prepaid  by  mail 
on  receipt  of  price. 


NICHOLS    AND    NOYES, 

117    WASHINGTON    STREET,    BOSTON. 


The  Publishers  request  special  attention  to  the  following  un- 
solicited testimonials,  which  hare  been  received  from  sources 
worthy  of  regard. 

From  Rev.  W.  A.  Stearns,  D.D.,  LL.D.,  President  of  Amherst  College. 
"  I  have  read  it  with  great  profit  and  admiration.  It  is  a  grand 
production,  — very  clear  and  satisfactory,  scientifically  considered ; 
very  exalted  and  exalting  in  spirit  and  manner ;  and  exhibiting  a 
wealth  of  appropriate  emotion  and  expression  which  surprises  me. 
May  the  life  and  health  of  the  author  be  spared  to  show  still 
further  that  God  is  and  that  His  works  are  great,  sought  out  of 
them  that  have  pleasure  therein." 

From  Rev.  Horace  Bushnett,  D.D. 

"  I  have  not  been  so  much  fascinated  by  any  book  for  a  long 
time, — never  by  a  book  on  that  particular  subject.  It  is  popu- 
larised in  the  form,  yet  not  evaporated  in  the  substance,  —  it 
tingles  with  life  all  through,  —  and  the  wonder  is,  that,  casting  off 
so  much  of  the  paraphernalia  of  science,  and  descending,  for  the 
most  part,  to  common  language,  it  brings  out,  not  so  much,  but  so 
much  more  of  the  meaning.  I  have  gotten  a  better  idea  of  Astron- 


2 


omy,  as  a  whole,  from  it  than  I  ever  got  before  from  all  other 
sources,  —  more  than  from  Enfield's  great  book,  which  I  once  care- 
fully worked  out,  eclipses  and  all. 

"  I  trace  the  progress  made,  and  the  methods  of  the  same,  and 
seize  on  the  exact  status  of  things  at  the  point  now  reached." 

From  the  Biblioiheco,  Sacra. 

"  This  is  a  remarkable  book,  —  one  of  the  most  remarkable 
which  has  proceeded  from  the  American  press  for  a  long  time.  It 
lifts  the  reader  fairly  into  the  heavens  and  unveils  their  glories. 
The  presentation  is  very  full  though  concentrated,  very  clear  and 
animating,  —  with  a  command  of  language  and  a  glow  of  eloquence 
which  is  quite  extraordinary.  The  last  lecture  is  hardly  less  than 
a  Te  Deum.  The  only  adverse  criticism  which,  on  reading  the 
preparatory  lecture,  we  were  inclined  to  make,  was,  that  the  almost 
impassioned  eloquence  with  which  it  opened  would  have  been 
more  impressive  further  on,  and  after  the  imagination  had  been 
excited  by  the  facts.  But,  after  finishing  the  last  Lecture,  we 
could  not  wonder  that  a  mind  so  full  of  the  great  facts,  and  of  the 
emotion  which  they  necessarily  kindle,  should,  on  seeing  his  own 
parish  charge  assembled  to  listen,  break  forth  in  strains  which  none 
but  a  mind  fully  roused  by  his  theme  and  his  audience  would 
have  been  able  to  utter.  No  person  can  read  through  this  volume 
without  mental  exaltation,  and  a  conviction*  of  the  peculiar  ability 
of  the  author." 

From  the  New  Englander, 

"  It  presents  an  admirable  resumf  of  the  sublime  teachings  of 
Astronomy,  as  related  to  natural  religion,  —  a  series  of  brilliant 
pen-photographs  of  the  Wonders  of  the  Heavens,  as  part  of  God's 
glorious  handiwork.  The  first  five  lectures  pass  the  science  in 
rapid  review ;  the  last  treats  of  the  Author  of  Nature,  as  related  to 
its  leadin*  features.  There  is  not  a  dry  page  in  the  volume,  but 
much  originality  and  vigor  of  style,  and  often  the  highest  elo- 
quence. It  is,  withal,  evidently  by  an  author  at  home  in  his  sub- 
ject, not  "  crammed "  for  the  task.  It  affords  a  fine  example  of 
what  an  intelligent  pastor  can  do,  outside  of  his  pulpit,  towards 
training  an  intelligent  people,  and  by  imparting  to  them  Nature's 


teachings,  leading  "through  Nature  up  to  Nature's  God,"  —  the 
God  of  Kevelation  as  well.  To  such  a  book  the  author  need  not 
hesitate  to  affix  his  name." 

From  Rev.  A.  P.  Peabody,  D.D.,  LL.D.,  Preacher  to  Harvard  University, 
and  Plummer  Professor  of  Christian  Morals. 

"  Permit  me  to  thank  you  for  a  work  in  which  you  have  effected 
a  rare  union  of  scientific  accuracy,  eloquent  diction,  and  rich  de- 
votional sentiment.  It  is  attractive,  instructive,  and  edifying.  It 
appears  at  a  time  when  science  needs,  as  never  before,  to  be 
redeemed  and  sanctified  by  faith  in  Him,  in  whom  are  hidden  all 
the  treasures  of  wisdom  and  knowledge.  And,  best  of  all,  it  does 
not  make  Keligion  cringe  to  Science,  but  maintains  her  in  that 
queenly  status  which  is  the  only  position  she  can  hold.  The  book 
must  do  great  good,  and  I  heartily  congratulate  you  as  its  author." 

From  Rev.  S.  H.  Hall,  D.D. 

"  Ecce  Coelum  is  much  more  than  a  book-success.  It  will  be 
honored  as  a  most  timely  and  admirable  treatise  to  put  into  the 
hand  of  thoughtful  young  people,  to  '  turn  off  their  minds  from 
vanity,'  and  lead  them  to  God." 

From  the  New-  York  Evangelist. 

"  This  unpretending,  though  elegant  little  volume,  gives  a  most 
admirable  popular  summary  of  the  results  of  Astronomical  Sci- 
ence. The  author  has  evidently  mastered  his  subject,  and  he  has 
presented  it  in  a  most  striking  manner,  adapted  to  the  comprehen- 
sion of  the  common  reader,  and  enriched  with  pertinent  illus- 
trations. The  book  is  perhaps  the  most  fascinating  treatise  on  the 
science  which  has  been  published  of  late  years,  ranking  indeed 
in  many  respects  with  that  of  the  late  lamented  and  eloquent 
Mitchell.  One  of  its  excellencies  is  that  it  does  not  hide  God 
'behind  his  own  creation.'" 

From  the  Religious  Herald. 

"  A  New  Book,  and  one  that  is  a  book,  worth  its  weight  in 
gold  or  diamonds,  for  it  is  full  of  gold  and  precious  gems,  —  dia- 
monds of  law  and  fact,  —  truths  beaming  with  celestial  light.  J 


speak  of  '  Ecce  Coelum/  from  the  pen  of  Rev.  ENOCH  F.  BURR, 
D.D.,  of  Lyme,  Conn.,  published  by  Nichols  &  Noyes,  Boston,  a 
duodecimo  of  198  pages.  Mr.  Burr  modestly  signs  himself  'A 
Connecticut  Pastor/  but  some  college  has  rent  the  vail  and  written 
out  his  full  name,  and  added  to  it  a  D.D.  So  much  the  better  for 
Connecticut  and  for  the  world.  Such  light  as  the  book  contains 
ought  not  to  be  under  a  bushel. 

•'  These  six  Parish  Lectures  are  a  masterly,  vivid,  easy,  sub- 
lime presentation  of  the  enchanting  facts  of  Astronomy.  They 
are  adapted  to  all  classes,  —  the  learned  and  the  unlearned.  The 
astounding  glories  of  the  skies  are  tempered  to  our  humble  eyes. 

"Let  all  read  the  book,  old  and  young.  Let  it  be  found  in 
every  school,  in  every  library,  and  .in  every  home  where  wisdom 
is  invoked.  Read  it,  and  you  will  exclaim,  what  glorious  light  it 
sheds  from  the  throne  of  God  upon  the  lonely  pathway  of  man !  " 

From  C.  H.  Balsbaugh,  of  Pennsylvania. 

"  It  is  certainly  a  wonderful  little  book.  How  the  world 
shrinks  into  an  atom  as  we  follow  the  lofty  soarings  of  the  '  Con- 
necticut Pastor/  I  never  knew  rightly  what  Dr.  Young  means 
by  saying,  *  an  undevout  Astronomer  is  mad ; '  but  I  now  see  and 
feel  the  power  and  beauty  of  the  expression.  Such  a  book  cannot 
be  read  without  laying  upon  us  the  responsibility  of  a  new  charge 
from  heaven.  After  contemplating  such  grandeur,  we  instinctively 
exclaim,  '  What  is  man  that  Thou  art  mindful  of  him  ?  '  '• 

From  Hon.  S.  L.  Selden,  Late  Chief  Justice  of  New  York. 
"  A  beautiful  book.  I  admire  it  for  the  elegance  of  its  style,  as 
well  as  for  the  lucid  and  able  manner  in  which  it  presents  the 
noblest  of  the  sciences.  It  will  prove,  I  think,  very  valuable,  not 
merely  for  the  knowledge  it  communicates,  but  as  suggestive  of  a 
line  of  noble  and  elevated  thought.  And  I  am  much  pleased  to  see 
from  the  numerous  notices  which  have  come  under  my  observa- 
tion that  my  estimate  is  confirmed  by  many  persons  of  the  first 
capacity  for  judging.  To  have  written  a  work  which  receives 
and  deserves  such  very  high  praise  from  scholars  and  men  of 
science  cannot  but  be  a  source  of  great  gratification  to  the 
author." 


CONTENTS. 


I.  PREPARATORY. 

1.  USES 9 

2.  HISTORY 16 

3.  INSTRUMENTS  OF  INVESTIGATION       .       .       .       .  ao 

II.  THE  SKY. 

1.  ASPECT     .       .       .       .       .       .       .       .       .       .       .       .33 

2.  NATURE 39 

3.  NATURE  OF   CONTENTS 43 

4.  ARRANGEMENT  OF  CONTENTS 49 

III.    SATELLITE  SYSTEMS. 

'EXAMPLE— EARTH  AND  MOON. 

1.  DIURNAL  REVOLUTIONS 66 

2.  MUTUAL  DISTANCE .        .  70 

3.  SHAPES  AND  SIZES 71 

4.  MUTUAL  GRAVITATIONS 77 

5.  MASSES  AND  DENSITIES 81 

6.  ORBITS                     . 84 

7.  MUTUAL  ASPECTS 87 

5 


O  CONTENTS. 

IV.  PLANET  SYSTEMS. 

EXAMPLE  —  SOLAR  SYSTEM. 

x.    ORDER  OF  BODIES 93 

2.  PERIODS  . 103 

3.  DISTANCES  FROM  SUN 105 

4.  SHAPES  AND   INCLINATIONS  OF  ORBITS    .       .       .in 

5.  SIZES 115 

6.  VELOCITIES 117 

7.  MASSES  AND  DENSITIES 118 

8.  PERTURBATIONS 120 

V.  HIGHER  SYSTEMS. 

x.    SUN  SYSTEMS 125 

2.  GROUP  SYSTEMS 137 

3.  CLUSTER  SYSTEMS 138 

4.  NEBULA  SYSTEMS .  140 

5.  ULTERIOR  SYSTEMS 146 

6.  ULTIMATE  SYSTEM 148 

VI.  AUTHOR  OF  NATURE, 

As  RELATED  TO  ITS  LEADING  FEATURES. 

x.    VASTNESS 159 

2.  VARIETY  IN  UNITY '      ...  163 

3.  FINISH  OF  MINIMA 168 

4.  WISDOM 171 

5.  DYNAMICS i77 

6.  RELATION  TO  LAW 182 

7.  RELATION  TO  TIME  AND   MOTION        .       .       .       .188 

8.  MYSTERY  .       .        .193 


L 

PREPARATORY. 


I.  PREPARATORY. 

1.  USES 9 

2.  HISTORY 16 

3.  INSTRUMENTS  OF  INVESTIGATION                              .  ao 


FIRST    LECTURE. 


PREPARATORY. 

A  STRONOMY,  the  science  of  the  stars,  does 
.11.  not  limit  itself  to  those  bright  points  in  the 
vault  of  evening  which  are  commonly  called 
stars,  but  treats  of  the  Sky  with  its  whole  star- 
like  belongings  —  Sun,  Moon,  Planets,  Comets  — 
whatever  of  this  general  nature  reveals  itself  in 
the  entire  round  Heavens. 

What  is  the  use  of  Astronomy  ?  Had  this 
question  been  asked  a  few  centuries  ago,  most 
intelligent  persons  would  have  said  that  its 
chief  use  was  to  aid  astrology.  Somehow,  men 
had  conceived  the  idea  that  the  fortunes  of 
individuals  and  nations  were  bound  up  with  the 
aspects  and  places  of  the  heavenly  bodies,  and 
could  be  predicted  from  them.  It  was  univer- 
sally believed  that,  could  the  places  of  certain 
bodies  in  the  sky  at  the  birth  of  any  person  be 
well  ascertained,  it  would  be  possible  to  infer  the 
general  character  of  his  lot  in  life  and  its  criti- 
cal periods.  Here  was  grand  motive  for  study. 

9 


10  FIRST   LECTURE. 

Men  have  always  had  great  taste  for  being  pro- 
phets and  hearing  prophets  ;  so,  with  infinite  zeal 
and  pains,  they  watched  the  mazy  heavens,  and, 
out  of  such  glittering  fractions  of  information 
as  they  could  gather,  built  up,  as  their  chief 
use,  a  stupendous  system  of  fortune-telling  whose 
Twelve  Houses,  whose  Lords  of  the  Ascendant, 
whose  Horoscopes  and  Nativities,  were  the  busi- 
ness of  sages,  and  the  trust  of  monarchs  and  the 
people  for  thousands  of  years. 

It  is  well  that  we  have  some  better  reason 
than  its  astrological  uses  to  give  for  studying  the 
Science  of  the  Sky. 

See  where  the  sun,  with  face  of  insufferable 
splendor,  goes  swimming  through  the  day  ;  see 
where  the  soft  and  silver  moon,  with  fleets  of  stars, 
gqes  swimming  through  the  night !  What  an 
eloquent  silence  1  There  they  shine  and  move, 
perhaps  wonderfully  achieve  —  hosts  upon  hosts ; 
but  there  is  no  celebrating  pomp  of  sounds, 
only  an  all-embracing  pomp  of  silence  —  not  a 
whisper,  not  a  rustle,  through  all  the  vasty  dome. 
Our  dinned  ears  and  hearts  are  soothed.  Our 
petty  cares  and  excitements  are  hushed.  Both 
body  and  soul  are  insensibly  calmed  and  refreshed 
as  we  gaze  into  the  immeasurable  stillness. 

Was  ever  so  noble  a  sight !  What  kindly  in- 
terweavings  of  the  great  and  the  lovely — what  gor- 
geous competitions  and  combinations  of  the  majes- 
tic and  the  beautiful  —  and  all  steeped  in  the 


USE    OF  ASTRONOMY.  H 

grave  glory  of  immemorial  and  supreme  antiquity. 
The  sky  does  not  look  old.  Other  books  show  sad 
marks  of  the  passing  years.  Their  pure  white  sul-^ 
lies.  Their  varnished,  sharp-cut  characters  grow 
dull  and  vague.  Scars  and  molds  and  odors  of  de- 
cay gather  upon  them.  Not  so  with  this  pageant 
book  opened  above  us,  this  illuminated  missal  of 
the  heavens.  It  shows  a  page  as  delicately  fair 
and  fresh  as  if  it  had  just  come  from  the  hands 
of  its  Author.  And  yet  it  is  the  world's  ancient- 
est  heir-loom,  the  issue  of  the  eldest  dawn  :  and, 
as  we  look  upon  its  broad  and  pictured  page, 
we  are  reverently  aware  that  the  same  shining 
scripture  met  the  gaze  of  famous  empires  long 
since  dead  and  buried ;  of  those  old  men  of  renown 
whose  forms  loom  gigantically  on  the  outskirts 
of  tradition ;  of  him,  hoarest  ancient  of  all,  the 
Old-Testament  Adam.  It  is  a  joy  and  an  exalta- 
tion to  peruse^  such  a  Natural  Bible. 

And  then  it  is  so  accessible !  Not,  like  some 
rare  old  volume  of  price,  hid  away  from  the 
people  at  large  in  piles  of  granite  architecture ; 
railed  off  heavily  from  the  curious  handling  and 
close  inspection  of  most  of  such  as  are  allowed 
to  roam  the  stately  halls  ;  permitted  to  unclasp 
only  under  the  careful  hands  and  cultured  eyes 
of  sages  and  princes  —  not  such  is  this  azure 
volume  above,  printed  and  pictured  in  silver  and 
gold.  It  is  a  book  for  the  people.  Its  outspread 
page  invites  study  from  all  quarters,  by  day  and 


12  FIRST   LECTURE. 

by  night.  One  can  feast  his  eyes  on  it  as  freely 
as  another.  If  it  has  any  valuable  secrets,  any 
precious  wisdoms  in  it,  one  is  just  as  welcome  as 
another  to  do  what  lie  can  toward  finding  them. 
God  permits  no  censorship.  His  printing  is  a  true 
publishing.  With  both  hands  he  has  issued  his 
astronomy ;  has  put  it  in  characters  large  and 
shining  enough  to  be  within  the  range  of  all  eyes  ; 
has  opened  it  as  wide  as  wide  can  be,  and  laid 
it  across  the  sky's  fair  face  for  all  who  choose  to 
examine,  stand  they  at  palace-gates,  stand  they 
at  cabin-doors,  stand  they  in  the  silent  domes  of 
sky-piercing  observatories,  stand  they  on  the  rat- 
tling mid-road  of  affairs.  All  classes  welcome 
—  welcome  to  that  divine  calm,  to  that  refined 
and  exalting  pleasure,  to  that  jubilee  of  sight 
and  poetry  and  art,  to  that  feast  of  the  gods ! 

And  not  only  to  this  sensuous  and  aesthetic 
banquet  which  lies  spread  on  the  golden  surface 
of  things  for  all  who  have  eyes  and  souls,  but 
to  the  more  interior  and  recondite  stores  of  which 
these  others  are  mere  tokens  and  crumbs.  For 
the  sky  is  not  only  an  accessible  book,  but,  in 
these  last  days,  an  interpreted  one.  It  has  been 
translated  out  of  its  aboriginal  hieroglyphics,  put 
into  the  world's  vernacular,  done  into  alphabet 
even,  as  to  its  most  essential  facts.  The  inter- 
pretation was  hard.  Sometimes  it  seemed  as  if  it 
would  never  be  made.  It  actually  took  great 
men,  and  many  of  them,  to  make  it ;  and  many  a 


USE    OF  ASTRONOMY.  13 

long  age  crept  away  while  the  work  was  being 
done.  But,  lo !  done  it  is  at  last ;  and  the  re- 
sults, though  not  the  methods,  are  now  level  with 
the  commonest  men.  And  they  are  exceedingly 
serviceable  results.  Once,  men  could  not  see  an 
eclipse  or  a  star  with  a  tail  to  it  without  infer- 
ring pestilence  and  war  ;  could  not  even  see  a 
bloody  sun  or  shooting  star  without  fearing  na- 
tional disaster  and  the  fall  of  thrones.  But  now 
humanity  no  longer  falls  a-trembling  at  the  signs 
of  heaven.  The  progress  of  astronomical  science 
has  freed  us  from  our  superstitious  terrors.  We 
leave  such  panics  to  centuries  ago  and  the  hea- 
then. Thanks  to  the  sages  who  have  interpreted 
to  us  the  Sibyls  of  the  sky !  Thanks  to  them,  too, 
that  commerce  no  longer  rows  her  scant  and 
Liliput  shipping  in  timid  adventure  within  her 
native  creeks,  and  along  her  native  shores.  To 
the  science  of  the  stars  we  owe  the  safety  and  au- 
dacity with  which  unlimited  canvas  now  stretches 
across  the  widest  seas  and  darkest  nights.  By 
the  improvements  it  has  been  the  means  of  in- 
troducing into  mathematics  and  observation,  it 
has  raised  the  whole  body  of  our  art  and  sci- 
ence ;  in  fact,  created  large  portions  of  each. 
Scarcely  a  branch  of  business  or  knowledge,  how- 
ever humble,  or  however  high,  but  is  debtor,  in 
one  way  or  another,  to  astronomical  investiga- 
tions. Astronomers  first  taught  men  the  art  of 
questioning  Nature.  They  were  the  first  inter- 


14  FIRST  LECTURE. 

preters  of  her  that  deserved  the  name,  the  first 
to  give  dazzling  and  triumphant  examples  of  the 
way  of  extorting  secrets  from  her  close-fisted 
keeping.  In  education,  also,  astronomy  has  been 
of  most  material  service.  A  large  and  generous 
culture  of  the  mind  requires  familiarity  with  a 
wide  variety  of  ideas.  We  need  to  be  trained  to 
refined  distinctions,  to  subtle  analyses,  to  acute- 
ness  of  thought ;  and  for  this  purpose  other  sci- 
ences will  answer  better  than  astronomy.  But 
we  also  need,  still  more,  culture  in  breadth  and 
dignity  and  gravity  of  ideas,  in  comprehension 
and  solidity  of  understanding,  in  elevation  and 
durable  glow  of  imagination  and  character  ;  and, 
for  this  purpose,  no  branch  of  secular  knowledge 
can  compare  with  the  science  of  the  stars.  This 
science  is  worth  more  than  all  the  fictions  and 
poems  in  the  world  as  a  judicious  cultivator  of 
the  imagination  and  corrector  of  insipidity  and 
tarneness  of  character.  It  is  universally  admit- 
ted to  be  the  sublimest  of  the  natural  sciences. 
It  is  a  poem  as  well  as  a  science  —  the  best  ex- 
ample we  have  of  polished  completeness  in  a 
science,  and  the  noblest  specimen  we  have  of  an 
epic  poem.  Not  Milton,  not  Homer,  ever  sang 
so  sweetly  and  loftily  as  do  the  chief  theorems  of 
astronomy.  And  certainly,  if  one  would  get  just 
ideas  of  the  grandeur  and  possibilities  of  the  hu- 
man mind,  in  no  way  could  he  better  accomplish 
his  purpose  than  by  noticing  what  great  astro- 


USE    OF   ASTRONOMY.  15 

nomical  problems  that  mind  has  grappled  with 
and  conquered.  It  has  been  the  war  of  Jupiter 
with  the  Giants.  When  we  look  at  the  mighty 
secrets  that  men  have  wrested  out  of  that  starry 
page  above  us,  we  say  softly  and  reverentially 
to  ourselves,  "In  the  image  of  God  made  he 
them/'  We  also  feel  that  what  man  has  done 
man  can  do.  We  are  encouraged  for  the  future  of 
science,  the  future  of  art,  the  future  of  every  thing 
requiring  great  endowments  in  man.  But,  after 
all,  the  most  interesting  and  useful  thing  about 
astronomy  is  the  illustration  it  pours  on  the  attri- 
butes and  glory  of  the  Supreme  Being.  Let  it  be 
repeated,  that  ancient  sentiment,  "  An  undevout 
astronomer  is  mad."  If  one  can  thoughtfully 
pace  up  and  down  the  star-sown  fields  of  astrono- 
omy  and  not  conceive  a  feeling  of  religious  awe, 
as  in  the  presence  of  Incomprehensible  Almighti- 
ness,  he  must  be  a  rare  man,  a  sinner  above  all  the 
Galileans.  The  fullest  force  of  this  inspired  say- 
ing, "  for  the  invisible  things  of  Him  are  clearly 
seen,  being  understood  by  the  things  that  are 
made,  even  his  eternal  power  and  godhead,"  —  I 
say,  the  fullest  force  of  these  words  is  only  felt 
by  him  whose  thoughts,  leaving  the  diminutive 
objects  of  this  world,  have  gone  voyaging  through 
the  inexhaustible  wonders  of  the  firmament  and 
gazed  intelligently  on  the  files  of  that  infinite  ar- 
mada of  luminaries,  which,  in  exquisite  harmony 
and  solemn  pomp,  cruise  up  and  down  yonder 
shoreless  ocean  of  the  heavens. 


16  FIRST   LECTURE. 

Astronomy  is  universally  admitted  to  be  the 
most  ancient  of  all  the  natural  sciences.  How- 
ancient  none  can  tell.  Neither  history  nor  tra- 
dition carries  us  back  to  its  beginning.  We  can 
learn  nothing  of  its  founder  or  founders.  Their 
very  names  are  lost  in  the  darkness  of  the  primal 
ages.  At  the  time  when  we  get  our  first  clear 
view  of  the  science,  viz.  two  or  three  thousand 
years  before  Christ,  it  had  already  made  very  con- 
siderable progress.  Some  say  that  Chaldea,  with 
its  beautiful  atmosphere,  was  the  native  country 
of  astronomy  ;  others  stand  up  stoutly  for  Egypt, 
"mother  of  sciences";  while  still  others  think 
favorably  of  the  claims  of  India,  with  its  most 
ancient  of  all  astronomical  tables,  the  tables  of 
Tirvalore,  and  its  most  ancient  and  studious  Brah- 
mins. Who  know  ?  Not  even  those  persons  who 
have  taught  that  the  cradle  stood  in  this  country 
by  claiming  that  here  stood  the  cradle  of  the  hu- 
man race  —  that  fossils  of  the  human  period  in  the 
United  States  go  back  to  a  remoter  antiquity  than 
those  in  any  other  part  of  the  globe  !  Astronomy 
was  cultivated  in  very  remote  times  —  hundreds 
and  perhaps  thousands  of  years  before  the  Chris- 
tian era  —  by  the  Chinese  as  well  as  by  the  East- 
Indians,  Egyptians,  and  Chaldeans.  Since  the 
time  of  reliable  history,  however,  the  science 
has  been  in  a  state  of  decay,  if  not  extinction, 
among  most  of  these  nations.  With  some  it 
has  long  been  one  of  the  totally  lost  sciences. 


HISTORY    OF   ASTRONOMY.  17 

We  look  in  vain  for  a  living  astronomy  through 
all  the  countries  of  the  East.  We  find  nothing 
but  a  fossil,  and  a  mutilated  fossil  at  that.  Civil 
troubles,  with  other  causes  perhaps,  killed  and 
buried  it  before  the  historic  period  in  all  those 
remoter  Oriental  lands.  In  Egypt,  however,  and 
subordinately  in  Greece,  the  science  continued 
to  live  and  occasionally  grow  till  within  times 
quite  modern.  The  world  will  not  willingly  let 
die  such  names  as  Thales,  Pythagoras,  Hippar- 
chus,  Ptolemy ;  nor  the  glory  of  that  famous 
Alexandrian  school,  which,  from  three  hundred 
years  before  Christ,  till  the  sack  of  Alexandria 
and  the  destruction  of  its  famous  library,  in  the 
seventh  century,  continued  to  toil  away,  and  not 
without  success,  on  the  heavens.  That  terrible 
vandalism  that  destroyed  the  garnered  wisdom 
of  so  many  centuries  suppressed  astronomical 
culture  in  the  West  for  nearly  a  thousand  years. 
The  old  Romans  were  fighters,  never  astrono- 
mers. Their  disjecta  membra,  the  middle  ages, 
were  fighters,  never  astronomers.  Meanwhile 
the  cast-away  science  found  a  home  among  the 
Arabs.  At  Bagdad,  under  the  caliphates  of  the 
Abassides,  arose  a  new  Augustan  age  for  all  sorts 
of  learning.  Equally  enlightened  and  powerful, 
those  splendid  monarchs  gathered  about  them- 
selves the  cultivators  of  knowledge  from  every 
quarter,  and  spared  neither  pains  nor  gold  to 
make  their  capital  the  focus  of  the  world.  And 


18  FIRST   LECTURE. 

they  succeeded.  While  it  was  unrelieved  mid- 
night in  Europe,  it  was  midnight  lit  up  by  cal- 
cium lights  in  Arabia.  Immense  attention,  in 
particular,  was  given  to  astronomy  ;  and  the 
mere  names  of  those  Saracenic  philosophers  who 
cultivated  this  and  other  branches  of  liberal 
knowledge  would  fill  a  volume.  Moreover,  it 
was  from  the  splendid  and  enlightened  king- 
dom which  the  Arabs  established  in  Spain  that 
astronomy  was  again  set  on  her  feet  in  the  rest 
of  Europe,  at  the  beginning  of  the  sixteenth 
century,  after  well  nigh  a  millennium  of  exile. 
After  all,  the  amount  of  real  discovery  in  the  heav- 
ens made,  up  to  this  time,  by  all  these  illustri- 
ous men  and  schools,  of  various  nations,  for  thou- 
sands of  years,  was  comparatively  small.  Many 
a  single  year  since  has  done  more  for  astronomy 
than  was  done  by  all  the  many  thousands  of  years 
before.  The  fact  is,  the  old  astronomers  were  de- 
stroyed by  their  theories  and  visionary  philoso- 
phies. Instead  of  carefully  observing  Nature  and 
drawing  their  systems  from  it,  most  of  them  first 
arbitrarily  formed  their  systems  and  then  en- 
deavored to  interpret  Nature  in  consistency  with 
them.  Like  many  people  now,  they  scorned  to 
begin  at  the  beginning.  They  wanted  to  build 
their  house  from  the  roof  downward,  instead  of 
building  it  from  the  foundation  upward  ;  wanted 
to  start  with  Euclid  and  Homer  and  figure  their 
way  back  to  a  knowledge  of  the  alphabet ;  wanted 


HISTORY   OF   ASTRONOMY.  19 

to  start  with  the  broadest  generalizations  of  sci- 
ence and  so  descend  on  particulars,  like  Plato, 
their  great  master  or  representative.  In  conse- 
quence very  little  was  accomplished,  considering 
the  prodigious  time  and  labor  expended.  It  was 
not  till  Prussian  Copernicus  and  his  immediate 
successors  cast  off  the  old  theories  and  way  of 
studying  Nature,  that  astronomy  can  be  said  to 
have  fairly  begun  her  triumphant  career.  The  in- 
cubus once  lifted,  she  then,  under  the  lead  of  such 
men  as  Tycho  Brahe,  Kepler,  Galileo,  Newton, 
went  forward  with  gigantic  strides.  Up  to  the 
present  time,  it  has  been  one  incessant  tramp  and 
thunder  of  discoveries.  Scarcely  would  one  great 
truth  flash  down  from  the  sky  before  men's  at- 
tention would  be  called  to  another.  Much  of  the 
time,  indeed,  these  truths  have  come  in  showers 
and  set  the  whole  sky  ablaze.  It  is  not  much  ex- 
aggeration to  say  that  the  heavens,  instead  of 
raining  stars  upon  us  once  every  November,  are 
raining  them  nearly  the  whole  time.  Like  the 
tributaries  of  some  Mississippi  or  Amazon,  con- 
tributions have  flowed  into  the  main  astronomical 
current  from  every  quarter  and  Christian  land. 
The  French  (a  wonderful  nation  for  every  thing 
save  religion  and  self-government)  have  particu- 
larly distinguished  themselves.  Since  Newton,  no 
names  in  science  so  glorious  with  achievement, 
to  none  will  a  grateful  posterity  so  freely  decree 
triumphs,  as  to  those  of  Clairaut,  La  Grange, 


20  FIRST   LECTURE. 

La  Place,  and  Arago.  The  English-speaking 
race  have  also  found  laurels  growing  in  the  sky 
and  have  liberally  plucked  them  —  witness  Flam- 
stead  and  Halley  and  Bradley  and  Maskelyne  and 
the  two  Herschels.  For  Germany  and  Russia, 
are  the  great  names  of  Bessel  and  Argelander  and 
Struve  and  Maedler  —  names  inseparably  con- 
nected with  some  of  the  most  recent  and  dazzling 
successes  of  astronomy.  They  have  added,  not 
cities,  but  provinces,  to  her  empire.  Altogether, 
the  astronomers  of  the  last  three  hundred  years 
have  given  us  the  most  extensive,  sublime,  and 
complete  science  to  be  found  in  the  world. 

And  by  what  means  were  these  grand  results 
reached  ?  The  naked  eye  has  done  something — 
done  much.  In  remote  times,  men  had  nothing 
else  with  which  to  explore  the  heavens :  but  this, 
with  the  help  of  the  pure  Chaldean  air  and  leis- 
urely shepherd  life  ;  this,  with  the  help  of  the 
perpetually  cloudless  Egyptian  sky  and  the  free, 
secluded  life  of  the  cultured  and  inquisitive 
priesthood,  was  sufficient  to  lay  the  foundations 
of  astronomy.  Even  to  this  day,  the  unaided 
eye  lias  made,  and  it  need  not  despair  of  still 
making,  discoveries  in  the  heavens.  Next,  as- 
tronomy is  indebted  to  artificial  instruments  —  to 
telescopes,  and  instruments  for  measuring  angles. 
Contrivances  for  measuring  the  angular  distances 
of  the  heavenly  bodies  from  each  other  were  first 
used  about  three  hundred  years  before  Christ,  at 


INSTRUMENTS    OF   INVESTIGATION.  21 

Alexandria.  They  were  very  rude  ;  so  much  so, 
that  Hipparchus  and  Ptolemy  considered  it  a  great 
achievement  to  measure  angles  of  10' — about  one- 
third  of  the  moon's  diameter  as  it  appears  to  the 
eye.  But  even  such  rude  approximations  to  the 
places  of  the  stars  accomplished  several  discover- 
ies, and  gave  the  charts  and  catalogues  which 
have  contributed  to  still  more  and  greater  dis- 
coveries in  modern  times.  Tycho  Brahe  made 
great  improvements  on  the  instruments  of  pre- 
ceding astronomers.  He  found  himself  able  to 
measure  angles  of  10"  —  an  accuracy  sixty  times 
greater  than  Hipparchus  could  command.  Hence 
another  instalment  of  discoveries.  At  the  present 
time  we  have  goniometers  of  wonderful  beauty 
and  exactness  —  almost  an  equal  feast  to  the  eye 
of  the  poet  and  to  that  of  the  mathematician  — 
enabling  us,  by  management,  to  reach  an  accuracy 
ten  thousand  times  greater  than  was  obtained  by 
Tycho  with  his  improved  instruments  three  hun- 
dred years  ago ;  enabling  us  to  measure  celestial 
arcs  no  larger  than  a  thousandth  part  of  a  second. 
It  is  this  last  style  of  accuracy  that  has,  within  a 
few  years,  enabled  us  to  find  the  distances  from  us 
and  from  eacli  other  of  some  of  the  fixed  stars,  so 
called,  as  well  as  other  results  scarcely  loss  won- 
derful. But  these  exact  instruments  and  their 
splendid  contributions  to  astronomy,  are  largely 
due  to  two  other  means  of  discovery,  viz.  obser- 
vatories and  optical  glasses.  To  secure  firm  sup- 


22  FIRST   LECTURE. 

port  for  instruments,  to  lift  them  above  the  vapors 
that  more  or  less  always  lie  along  the  surface  of 
the  ground  and  give  to  them  a  large  and  unob- 
structed horizon,  massive  and  lofty  towers  have 
been  built.  On  such  a  tower — Urauiberg,  he 
called  it  —  Tycho  placed  his  instruments  and 
made  his  discoveries.  On  such  towers,  num- 
bered by  hundreds  and  fitted  up  like  palaces  for 
every  sort  of  celestial  observation,  a  thousand 
astronomers  now  watch  out  the  night  all  over 
Christendom  —  at  Paris,  at  Greenwich,  at  Pul- 
kova,  at  Washington.  Observatories  are  the  ful- 
crums  of  astronomy.  They  are  the  war-towers 
from  which  we  can  best  attack  the  skies.  If  the 
Tower  of  Babel  had  only  been  designed  for  such 
use,  as  certain  incautious  persons  have  suggested, 
there  would  have  been  much  good  sense  in  it ! 

At  Florence,  in  the  Grand-Ducal  palace,  there 
is  a  room  called  the  Temple.  The  walls  are  in- 
laid with  marble  and  jasper.  The  ceiling  glows 
with  superb  frescoes.  In  niches  about  the  apart- 
ment are  disposed  numerous  marble  busts  —  por- 
traits —  in  the  best  style  of  recent  art.  At  the 
center,  the  gem  and  significance  of  the  whole, 
stands  a  life-size  statue  —  also  a  portrait  —  in 
whose  snowy  marble  features  one  recognizes,  not 
only  the  majesty  of  art,  but  also  the  majesty  of  a 
well-known  sage  whose  single  name  is  sufficient 
riches  for  a  country.  Here,  in  1840,  met  the 
Italian  men  of  science  to  dedicate  the  proudest 


INSTRUMENTS    OF   INVESTIGATION.  23 

cabinet  of  the  Medici  to  the  great  memory  of 
Galileo  Galilei,  whose  statue  that  is,  whose  dis- 
ciples' busts  those  are,  whose  leading  life-events 
that  glowing  ceiling  commemorates  —  Galileo,  the 
first  telescopic  explorer  of  the  heavens.  Well  did 
he  deserve  the  honor.  His  single  renown  more 
honors  his  native  city  than  do  all  her  grand  dukes, 
than  would  permanent  rank  as  capital  of  Italy. 
And  here,  in  a  press  by  the  wall,  is  the  very  tele- 
scope with  which  he  made  his  discoveries  —  two 
curved  glasses  rudely  fastened  in  a  rude  tube, 
all  made  with  his  own  hands.  With  this  simple 
instrument  he  created  a  new  era  in  astronomy. 
With  it  he  poured  on  the  age  such  a  succession 
of  wonders  that  foolish  Rome  feared  that  the  im- 
movable foundations  of  Holy  Scripture  would  all 
be  swept  away  by  the  deluge  of  innovations.  As 
if  her  interpretations  of  the  Bible  were  the  Bible 
itself !  Since  then,  the  telescope  has  been  bravely 
plucking  laurels  from  the  sky  almost  incessantly. 
Made  reflecting ;  made  achromatic ;  enlarged  from 
an  object-glass  of  two  inches  to  one  of  eighteen, 
and  from  a  speculum  of  six  inches  to  one  of  six 
feet;  equatorially  mounted,  with  all  the  appli- 
ances for  easy  motion,  exact  adjustment,  and  ex- 
tremest  nicety  of  measurement ;  planted  in  pa- 
latial observatories  where  all  the  heavens  look  in 
at  the  revolving  dome  and  where  scarcely  a  tre- 
mor of  storms  can  find  its  way  through  the  solid 
misonry  ;  supported  on  either  hand  by  Photo- 


2-4  FIRST   LECTURE. 

graphy  and  Telegraphy  —  in  short,  the  Great  Re 
fractor  of  Pulkova  or  the  Great  Reflector  of  the 
Earl  of  Rosse  —  the  telescope  of  late  years  is  still 
pushing  incessant  conquests  in  every  direction 
through  the  sky.  Formerly,  the  telescope  was 
one  ;  now  it  is  e  pluribus  unum;  and  from  thou- 
sands of  Uranibergs,  public  and  private,  the  won- 
der-working tube  is  nightly  run  out  against  the 
sky,  till  the  civilized  world  fairly  bristles  like 
a  battery  in  time  of  active  war;  and  competing 
observers,  under  the  spur  of  a  generous  emula- 
tion, almost  nightly  bring  down  upon  the  earth 
some  mighty  truth,  or  the  promise  of  one,  by 
their  voiceless  celestial  artillery. 

Not  long  after  the  invention  of  the  telescope, 
the  means  of  astronomical  investigation  received 
another  accession  of  at  least  quite  as  great  impor- 
tance. I  refer  to  that  branch  of  the  mathematics 
called  by  Newton,  one  of  its  inventors,  Fluxions, 
but  now  universally  known  among  scientific  men 
under  the  name  of  the  Differential  and  Integral 
Calculus.  It  is  a  species  of  higher  algebra ;  and 
its  peculiarity  consists  in  considering  all  finite 
quantities  as  expressible  by  the  ratio  of  two  in- 
finitely small  quantities  to  each  other.  It  is 
found  that  this  mode  of  considering  quantities 
has  in  it  a  mysterious  and  subtle  energy  for  the 
resolution  of  problems  of  the  higher  order,  be- 
yond any  thing  known.  It  is  a  natural  magic.  It 
is  the  quintessence  of  dynamics.  The  old  geom- 


INSTRUMENTS    OF   INVESTIGATION.  25 

etry,  both  synthetic  and  analytic,  is  a  mere  infant 
compared  with  it.  No  one  is  now  considered  half 
equipped  for  astronomical  research  unless  he  can 
wield  this  splendid  instrument.  Taking  certain 
facts  given  by  observation,  together  with  the  New- 
tonian law  of  gravitation  that  every  particle  of 
matter  attracts  every  other  particle  with  a  force 
proportioned  directly  to  its  own  quantity  of  mat- 
ter and  inversely  to  the  square  of  the  distance 
between  them  —  taking  these  as  its  fulcrum,  the 
Calculus  has  proved  itself  more  than  the  lever  of 
Archimedes ;  for  that  moves  only  one  world,  this 
moves  all  the  heavens. 

To  see  the  feats  of  this  Calculus  makes  one 
think  of  days  of  enchantment.  I  have  a  supreme 
confidence  that  none  of  you  have  ever  heard  this 
Arabian  history  of  what  anciently  happened  to 
one  of  the  Genii.  It  seems  that  this  good  mon- 
ster, who  was  as  tall  as  a  mountain  and  as  strong 
as  an  earthquake,  had,  on  a  certain  occasion, 
amused  himself  by  endeavoring  to  squeeze  his 
huge  figure  into  a  little  enchanted  black  bottle. 
At  last  he  succeeded.  Suddenly  the  cap  flew 
down  and  he  was  caught.  Some  thousands  of 
years  afterwards,  a  poor  man,  while  at  his  work 
one  day  and  thinking  how  hard  it  was  with  his 
best  efforts  to  make  a  living,  stumbled  on  this 
same  little  bottle.  "  Let  me  out  —  let  me  out!  " 
cried  the  bottle  in  a  half -suffocated  whisper. 
"  Can't  do  it,"  quoth  the  man,  at  once  aware  of 


26  FIRST  LECTURE. 

his  good  fortune,  — "  can't  do  it."  "I  will  do 
any  thing  you  want  if  you  will,"  begged  the  pris- 
oner. "  Will  you  take  away  that  great  mountain 
between  me  and  the  city  —  will  you  turn  my  lit- 
tle tent  into  a  palace  —  will  you  fill  it  witli  gold 
and  precious  stones  — will  you  promise  by  all  that 
is  sacred  to  Genii,  by  the  Prophet  and  Alcoran 
and  Allah  ?  "  "  Yes,  I  promise."  After  some 
difficulty,  the  man  managed  to  find  out  the  secret 
of  the  spring-cap,  and  lifted  it ;  when,  swift  as  an 
arrow,  out  rushed  a  puff  of  blue  vapor,  which 
gradually  expanded  till,  as  tall  and  broad  as 
Mount  Shahak,  it  took  the  form  of  a  winged 
man.  Without  any  ado,  the  monster  took  up 
the  mountain  in  his  arms  and  walked  off  with 
it  a  few  steps,  say  a  hundred  miles  or  so,  and 
threw  it  down  in  a  valley  behind  Bagdad,  where 
he  who  chooses  can  see  it  at  this  day.  Then 
stepping  back,  he  caught  up  the  little  tent 
and  threw  it  up  into  the  sky  out  of  sight,  say- 
ing, "  Come  down  great,  come  down  precious." 
In  a  few  minutes,  a  cloud  came  settling  down 
on  the  spot  ;  and,  as  it  slowly  broke  away, 
the  man  discovered  minarets  and  towers  and,  at 
last,  a  whole  gorgeous  palace  of  marble,  fit  for 
the  Leader  of  the  Faithful  Himself.  Then  the 
Genius  plucked  a  leaf  from  a  majestic  palm  that 
waved  proudly  by  the  portal  and  wrote  certain 
strange  characters  on  it  with  his  finger.  Tearing 
it  int^  small  pieces,  he  puffed  them  away  in  every 


INSTRUMENTS    OF   INVESTIGATION.  27 

direction  with  his  breath.  Immediately,  long  lines 
of  Ethiopian  slaves  were  seen  coming  up  from  all 
quarters,  with  immense  stuffed  sacks  on  their 
shoulders  (I  suppose  twelve  men  in  these  degen- 
erate days  could  scarcely  lift  one  of  them)  ;  and, 
as  each  entered  the  palace  and  laid  his  sack  on 
the  floor,  he  laid  himself  down  also  by  the  side 
of  it  and  became  another  sack  as  large  and  full 
as  that  he  had  brought.  In  a  short  time,  the 
palace  was  full,  from  foundation  to  roof.  "  Come 
and  see,"  said  the  Genius.  Lo,  gold  Alraschids, 
Almansors,  and  Motassems  !  Lo,  carbuncles  and 
sapphires  and  diamonds  filled  every  apartment ! 
"  Have  I  kept  my  promise  —  am  I  free  ?  "  —  "Ay ; " 
said  the  enraptured  fellow,  "  and  well  have  you 
deserved  your  liberty."  — "  To  tell  the  truth," 
quoth  the  spirit,  "  I  have  been  so  long  in  that 
little  black  bottle  that  I  think  I  had  rather  stay 
there  than  anywhere  else.  When  you  want  me 
you  will  know  where  to  find  me."  So,  without 
any  more  ceremony,  he  doubled  himself  up  and 
squeezed  into  the  bottle  again.  Was  not  his 
name  Radib  ?  Was  not  that  poor  man  the  same 
Emir  Alabdes  by  whom  the  Caliph  Motassem  (for 
whom  Allah  be  praised),  with  ten  thousand  of  his 
attendants,  was  so  sumptuously  entertained  at 
his  marble  palace,  in  the  180th  year  of  the 
Hegira  ? 

I  say,  it  makes  one  think  of  such  an  Arabian 
Nights'  story,  when  he  looks  at  some  of  those  lit- 


28  FIRST   LECTURE. 

tie  equations  out  of  which  Clairaut  and  La  Place 
and  others  have  managed  to  evoke  such  prodi- 
gious dynamics  as  have  sufficed  to  enrich  them- 
selves and  their  race  with  uncounted  treasures 
of  fame  and  truth ;  as  have  sufficed  to  remove 
mountains  from  the  path  of  astronomy,  and  con- 
vert her  humble  tent  into  a  spacious  palace  filled 
with  unprecedented  gems  of  the  plundered  sky. 
How  much  does  yonder  star  weigh  ?  When  will 
yonder  hairy  star  come  back  ?  Suppose  five  worlds 
launched  in  vacancy  from  a  given  position,  with 
given  directions  and  velocities,  where  will  each  be 
twelve  thousand  years  hence  ?  Such  questions  as 
these  which  men  would  once  have  despaired  of 
answering,  and  even  greater  questions  the  terms 
of  which  cannot  properly  be  assumed  as  intelli- 
gible at  this  point,  the  Calculus  has  conquered 
and  dragged  in  triumph  at  its  chariot- wheels. 
And  still  this  prince  of  good  Genii  is  at  the  ser- 
vice of  astronomers.  He  does  not  care  for  his 
liberty.  He  still  likes  to  take  up  headquarters 
in  the  little  black  bottle  of  a  differential  equation. 
When  his  friends  want  something  great  done  they 
know  where  to  find  him.  And  I  should  not  be 
surprised  to  see  the  day  when  I  can  tell  of  new 
feats  of  his  doing,  quite  as  prodigious  as  any  yet 
recorded.  Do  not  doubt  it — he  is  as  strong  as 
ever.  The  race  of  Eulers,  Newtons,  and  La 
Places,  is  not  yet  dead.  Gifted  men  are  busily 
learning  the  secret  of  the  spring-cap.  And,  some 


INSTRUMENTS    OF   INVESTIGATION.  29 

fine  morning,  men  shall  read  on  the  bulletin  boards 
of  science  of  new  mountains  removed,  new  palaces 
built,  new  whole  commissariats  of  golden  and  dia- 
mond truths  established  for  astronomy  by  the  re- 
doubtable Radib  of  the  Differential  and  Integral 
Calculus. 


II. 
THE    SKY. 


31 


II.   THE  SKY. 

1.  ASPECT 33 

2.  NATURE 39 

3.  NATURE  OF  CONTENTS 43 

4.  ARRANGEMENT  OF   CONTENTS 49 


SECOND    LECTURE. 


THE     SKY. 

I  AM  to  explain  what  discoveries   have   been 
made  in  the  distant  sky.     To  do  this  to  the 
best  advantage,  we  must  have  a  picture  of  the 
sky,  with  its  leading  aspects  and  names,  fresh  in 
our  minds. 

So  let  us  imagine  this  structure  unroofed,  and, 
indeed,  well  taken  down  on  all  sides.  And,  to- 
night, let  us  further  imagine  that  some  tall  Genius 
is  kind  enough  to  brush  away  with  his  besom  the 
envious  clouds  —  those  ancient  and  unutterable 
enemies  of  the  astronomer.  We  seem  to  be  at 
the  center  of  an  immense  hollow  half-globe,  on 
the  distant  surface  of  which  appear  the  heavenly 
bodies.  If  it  were  day,  we  should  see  on  that 
remote  concave  the  yellow  sun :  it  being  night, 
we  see,  instead,  a  multitude  of  stars  and  the  moon 
with  its  silver  crescent.  Watch  the  host  for  a 
little  behind  some  building,  and  you  may  satisfy 
yourself  that  they  are  all  in  motion  towards  the 
west ;  that  is  to  say,  are  all  revolving  about  a 

3  33 


34  SECOND    LECTURE. 

line  drawn  through  where  you  are  sitting  and 
a  point  due  north,  but  elevated  about  40°  above 
the  horizon.  Notice  that  very  bright  white  star 
low  in  the  west :  that  is  Venus,  named  after 
the  Greek  and  Roman  goddess  of  beauty.  Yon- 
der, almost  overhead,  is  another  star,  of  scarcely 
inferior  brightness  but  of  more  masculine  hue : 
that  is  Jupiter,  named  after  the  king  of  the  clas- 
sical divinities.  East  of  the  zenith,  about  one 
third  of  the  way  down,  you  may  perceive  a  much 
smaller  star  of  ruddy  light  —  Mars  by  name  — 
appropriately  called  from  the  bloody  god  of  war. 
Do  you  see  that  small  star,  just  visible  to  the 
naked  eye,  almost  on  the  eastern  horizon  ?  Well, 
that  is  Saturn,  named  from  the  father  of  the  prin- 
cipal gods,  and  sufficiently  dim  to  represent  one 
who  is  said  to  have  had  the  very  unfatherly  and 
unhandsome  trick  of  eating  his  own  children. 
These  stars,  and  many  others  which  are  never 
seen  without  a  glass,  are  called  planets,  because 
they  wander  about  greatly  on  the  sky.  Besides 
these,  are  certain  other  bodies,  seen  only  occa- 
sionally, which  are  still  greater  wanderers  — 
comets  so-called,  hairy  stars  —  a  denser  part 
more  or  less  bright,  surrounded  by  a  haze  which 
often  is  found  expanded  into  a  pale  streamer  of 
prodigious  length. 

All  others  stars  bear  the  name  of  fixed  stars, 
because,  to  ordinary  observation,  there  is  little 
or  no  apparent  change  in  their  positions  with 


ASPECT.  35 

respect  to  each  other.  Some  of  these  bodies 
are  very  conspicuous,  real  princes  for  shining, 
and  so,  from  time  immemorial,  have  been  hon- 
ored with  proper  names.  There,  for  example,  is 
one  nearly  as  brilliant  as  Yenus  herself —  Sirius 
—  with  a  ray  as  frosty  and  keen  as  ever  glanced 
from  an  iceberg ;  another,  Aldebaran ;  another, 
Capella.  Nearly  half  way  up  the  northern  heaven 
is  a  star  by  no  means  bright,  but  which  has  been 
on  men's  lips  and  in  their  eyes  oftener  than  any 
other  star  whatever  —  the  star  by  which  ships 
have  steered,  and  armies  marched,  and  bondmen 
fled  —  the  North  Star.  Count  some  twenty  of 
the  brightest  of  the  fixed  stars  on  the  whole 
sphere :  these  astronomers  call  stars  of  the  first 
magnitude.  Count  some  sixty  of  the  next  bright- 
est :  these  are  of  the  second  magnitude.  Some 
two  hundred  of  the  next  order  of  brilliancy: 
these  are  of  the  third.  Six  orders  of  magnitude 
are  visible  to  the  naked  eye :  ten  orders  more 
include  those  seen  by  the  telescope. 
{  Notice  the  unequal  distribution  of  the  stars 
on  the  sphere.  Some  are  solitary,  some  in  little 
groups  and  clusters,  some  in  dense  masses  that  re- 
semble white  clouds;  while,  among  others,  there 
seem  no  well-defined  natural  divisions  —  they 
seem  sown  broadcast  and  carelessly  on  the  vault. 
That  group  of  five  stars  forming  the  letter  V  is 
called  the  Hyades  —  rainy  Hyades,  said  the  an- 
cients. That  cluster  a  little  further  to  the  west 


36  SECOND    LECTURE, 

is  the  Pleiades — Job's  Pleiades,  with  their  sweet 
influences.  And  here,  stretching  across  the  whole 
hemisphere,  like  a  white  fog-bank  with  torches  in 
it,  is  the  well-known  Milky  Way  which  the  old 
poets  tell  us  was  inadvertently  made  by  Hercules 
when  an  infant.  Other  objects  of  the  same  gen- 
eral appearance  are  disclosed  by  the  telescope 
in  various  quarters  of  the  heavens  —  nebulae,  so 
they  are  called. 

These  are  natural  divisions  of  the  heavenly 
bodies.  There  are  others  not  so  natural,  called 
constellations.  The  ancients  (no  one  knows  how 
ancient  they  were),  with  not  a  little  help  from 
the  moderns,  pictured  the  celestial  sphere  all 
over  with  figures  of  men  and  brutes  and  other 
objects,  so  as  to  show  almost  as  extensive  a  men- 
agerie as  was  collected  in  Noah's  ark :  indeed, 
the  very  ark  itself  is  there  ;  at  least  Noah's  dove, 
and  we  may  reasonably  suppose  the  ark  to  be 
not  far  off.  There  are  bears  and  lions  and  do- 
mestic animals  and  birds  and  fishes  and  reptiles, 
interspersed  with  warriors  and  nymphs  and  cen- 
taurs and  flying  horses,  all  dovetailed  into  each 
other  so  as  to  include  within  their  outlines  nearly 
all  the  stars.  If  the  leg  or  arm  of  a  human  figure 
could  not  be  so  disposed  as  to  cover  certain  stars, 
a  snake,  under  the  sonorous  name  of  Draco  or 
Hydra,  was  slipped  in  to  wind  in  and  out  till  the 
crooked  feat  was  accomplished.  Very  seldom  any 
resemblance  can  be  traced  between  the  constel- 


ASPECT.  37 

lations  and  the  various  objects  after  which  they 
are  called.  But  judge  for  yourselves.  Around 
the  North  Star  as  a  center,  describe  a  circle  that 
shall  just  touch  the  horizon.  Within  this  circle 
are  the  Great  and  Little  Bear,  an  immense  Dra- 
gon, royal  Cepheus  with  a  crown  on  his  head  and 
a  scepter  in  his  hand,  the  helmed  head  and  lifted 
falchion  of  Perseus,  and  on  her  chair,  with  a  palm 
branch  in  her  hand,  queenly  Cassiopeia.  Would 
you  think  it?  Around  the  point  directly  over- 
head, describe  another  circle  that  shall  just  touch 
the  other.  Within  this  new  circle  we  have,  tow- 
ards the  north,  beauteous  Andromeda,  with  fetters 
on  her  dainty  hands  and  feet ;  west,  Pegasus,  the 
winged  horse  ;  over  our  heads,  Aries  the  Ram ; 
next  east,  a  sort  of  celestial  Spain  — for  there  is 
shaggy  Taurus  in  full  career  with  horns  leveled 
at  giant  Orion,  who,  sworded  and  belted,  with  a 
lion-skin  in  one  hand  and  a  club  in  the  other,  is 
just  in  the  act  of  dealing  the  monster  a  rousing 
blow  between  the  eyes  that  will  undoubtedly  make 
him  see  stars.  Could  you  have  thought  it  —  such 
dignified  personages,  such  delightful  nymphs,  such 
illustrious  heroes,  such  magical  creatures,  such 
stirring  tourneys  and  bull  fights,  all  up  and  down 
the  arches  of  the  sky  !  However,  these  fanciful 
figures  answer  a  very  good  purpose  for  classify- 
ing and  describing  the  heavenly  bodies.  They 
distribute  them  into  celestial  nations  and  em- 
pires. 


38  SECOND    LECTURE. 

Provision  is  made  for  still  further  descrip- 
tion of  each  celestial  district,  to  any  degree  of 
minute  accuracy  that  may  be  desirable.  For 
many  purposes,  it  is  sufficient  to  tell  what  con- 
stellation a  star  is  in.  If  we  have  occasion  to 
be  a  little  more  precise,  we  can  say  in  what  part 
of  the  constellation  it  may  be  found,  as  in  the 
neck  of  Taurus  or  head  of  Andromeda.  To  pro- 
vide for  still  greater  precision  of  statement,  as- 
tronomers have  named  the  stars  in  each  constel- 
lation according  to  their  apparent  brightness. 
The  brightest  is  called  after  the  first  letter  of  the 
Greek  alphabet,  Alpha ;  the  next  brightest,  after 
the  second  letter,  Beta ;  and  so  on  through  all  the 
letters.  When  the  Greek  alphabet  is  exhausted, 
the  Roman  is  used  in  the  same  way.  If  both  al- 
phabets are  not  sufficient  to  take  account  of  all 
the  stars,  our  common  numerals  are  resorted  to. 
Thus  we  speak  of  Alpha  Leonis,  a  A^irginis,  61 
Cygni.  But  it  is  not  always  enough,  in  making 
a  map  of  a  country,  to  draw  its  boundaries  and 
set  down  within  them  the  various  cities  and  towns 
of  all  sizes,  in  something  like  their  relative  posi- 
tions :  some  geographical  purposes  require  that 
you  state  also  their  longitudes  and  latitudes;  that 
is  to  say,  their  distances  due  east  or  west,  and 
their  distances  due  north  or  south  of  a  given 
point  on  the  earth.  So,  for  some  astronomical 
purposes,  it  is  not  enough  to  bound  a  given  con- 
stellation and  set  down  its  stars  in  nearly  their 


ASPECT.  39 

relative  places,  with  their  names.  We  require  to 
know  the  longitude  and  latitude  of  each  star. 
We  must  know  how  far  it  is  from  a  certain 
great  circle  drawn  northerly  and  southerly  on 
the  sphere,  and  how  far  also  from  another  great 
circle  drawn  at  right  angles  to  the  other.  From 
very  remote  periods,  astronomers  have  been  en- 
gaged in  getting  this  latter  information.  Hip- 
parchus  made  out  a  catalogue  of  nearly  all  the 
stars  visible  to  the  naked  eye  at  Alexandria,  giv- 
ing the  latitude  and  longitude  of  each.  Herschel, 
La  Landc,  Mayer,  and  others,  have  constructed 
similar  catalogues,  but  giving  the  places  of  the 
stars  with  much  greater  accuracy. 

We  have  before  us  a  general  picture  of  the 
celestial  sphere,  with  the  more  usual  names  and 
classifications  of  the  objects  that  shine  upon  it. 
I  am  now  prepared  to  state  what  discoveries  have 
been  made.  What  is  this  seeming  immense  hol- 
low globe  of  the  heavens  ?  People  once  thought 
that  the  appearance  was  reality  —  that  they  were 
surrounded  at  a  great  distance  by  an  immense 
shell  of  crystal,  to  which  all  the  heavenly  bodies 
were  fastened.  At  a  later  period,  most  scholars 
thought  there  were  several  of  these  spheres:  each 
carrying  heavenly  bodies,  and  each  having  a  mo- 
tion peculiar  to  itself.  But  now  we  know  that 
there  is  nothing  of  the  sort  above  and  around 
us.  The  celestial  sphere  is  nothing  but  indefin- 
itely extended  space,  made  to  appear  colored  at 


40  SECOND    LECTURE. 

times  by  the  hue,  and  to  appear  rounded  always 
by  the  shape,  of  our  atmosphere.  There  is  noth- 
ing solid  yonder  to  which  the  celestial  bodies  can 
be  attached.  They  are  absolutely  hung  on  noth- 
ing—  though  Milton  ventures  to  take  poetic 
license,  and  hang  one  orb,  at  least,  by  a  golden 
chain.  This  idea  of  unsupported  heavenly  bodies 
was  quite  too  hard  for  the  remote  ancients  :  they 
must  have  spheres,  and,  not  a  few  of  them,  an 
elephant  and  a  tortoise  to  hold  up  the  earth  and 
heavens.  But,  finally,  it  filtered  through  the  ap- 
prehensions of  people  that  such  supporters  must 
themselves  need  support  quite  as  much  as  a  star ; 
also,  that  no  one  ever  saw  them,  or  otherwise 
credibly  knew  of  their  actual  existence.  So  they 
were  quietly  dispensed  with.  And  now  nothing 
remains  but  the  infinite  space,  which  we  certainly 
know  to  exist,  and  the  stars  which  we  certainly 
know  to  exist  in  it. 

Popularly  speaking,  this  great  space  which  en- 
virons us  on  all  sides,  and  contains  the  heavenly 
bodies,  is  empty.  It  is  substantially  a  vacuum. 
The  ancients  said  that  Nature  abhors  a  vacuum : 
if  so,  she  has  plenty  of  abhorring  to  do.  There 
is  no  atmosphere  pervading  space  :  we  could 
not  breathe  in  its  mid-intervals  one  single  mo- 
ment ;  there  is  nothing  there  that  our  senses 
could  perceive.  As  we  ascend  from  the  earth, 
we  find  the  air  gradually  become  thinner ;  and  La- 
Place  has  shown,  that,  after  a  few  miles,  it  must 


NATURE  OF  THE   CELESTIAL  SCENERY.       41 

cease  entirely.  Beyond  that  point,  very  large 
solid  bodies,  though  moving  with  enormous  ve- 
locity, are  found  to  encounter  not  the  smallest 
perceptible  resistance.  Their  places,  as  computed 
on  the  supposition  that  they  move  in  a  vacuum, 
are  such  as  we  actually  find  them.  At  the  same 
time,  there  is  reason  to  believe  that  the  vacuum 
may  not  be  absolutely  perfect.  Certain  facts 
which  have  come  to  light  in  late  years  have  con- 
vinced many  astronomers  that  we  must  allow 
the  existence  of  an  exceedingly  dilute  form  of 
matter  pervading  space.  It  is  nothing  that  we 
could  detect  in  the  ordinary,  sensible  way  :  we 
could  not  weigh  it,  nor  see  it,  nor  receive  sounds 
through  it ;  could  not  feel  it,  should  we  strike 
our  hands  through  it  with  our  utmost  force. 
Such  a  mere  nothing  is  it.  It  is  only  when  some 
very  light  body  goes  rushing  through  it,  at  the 
rate  of  thousands  of  miles"  an  hour,  that  its  pres- 
ence becomes  sensible  in  resisting  somewhat  the 
motion. 

If  we  could  visit  mid-space,  it  would  seem  a 
perfect  void,  also  dreadfully  cold  and  dark  and 
silent.  The  higher  we  go  into  our  atmosphere, 
the  colder  it  becomes.  All  mountain  summits, 
above  a  few  thousand  feet,  are  covered  with  per- 
petual snow.  Persons  ascending  in  balloons  at 
last  reach  a  cold  that  is  intolerable.  They  evi- 
dently approach  the  confines  of  an  eternal  winter, 
that,  for  silence  and  motionless  fierceness,  laughs 


42  SECOND    LECTURE. 

to   scorn   all   that   we   have   of   arctic   and  an- 
tarctic. 

According  to  the  calculations  of  Sir  John  Her 
schel,  we  have  only  to  go  fifty  miles  from  the 
earth's  surface  to  reach  — 132°  Fahrenheit.  Could 
we  suddenly  set  down  any  moist  thing  at  this 
point,  it  would  instantly  explode  like  a  pistol, 
though  without  sound  (for  mid-space  is  sound- 
less as  well  as  matterless),  and  turn  to  stone  as 
if  touched  by  a  magician's  wand.  And  if,  at  this 
short  distance  from  the  earth  and  sun,  space  is  so 
cold,  what  must  it  be  in  those  remote  vacancies 
where  the  sun  shows  as  a  mere  star  ?  In  thought, 
we  sail  away  most  comfortably  among  the  con- 
stellations, without  furs  or  overcoat  ;  and  per- 
haps our  fancies  make  nothing  of  stopping  whole 
hours  in  mid-heaven,  leaning  against  the  chair 
of  Cassiopeia,  or  grasping  the  horns  of  Taurus,  to 
admire  the  glory  of  the  trooping  stars  ;  but  one 
real  bodily  expedition  of  the  sort  would  forever 
cure  us  of  such  fancies.  Perhaps  of  some  others 
also ;  for,  when  our  thoughts  go  yachting  it 
through  space,  they  are  very  apt  to  take  with 
them,  not  only  our  genial  parlor  temperature, 
but  also  our  pleasant  earthly  light  and  colors. 
But,  in  point  of  fact,  the  starry  spaces  are  awfully 
dark.  Those  who  visit  the  higher  regions  of 
our  atmosphere,  by  mountains  or  balloons,  tell  us 
that  the  pleasant  blue  gradually  passes  into  an 
intense  black.  At  last,  the  stars  glitter  on  a 


NATURE   OF  TEE  HEAVENLY  BODIES.         43 

background  of  perfect  jet.  To  an  observer  out 
in  mid-heaven,  the  whole  sphere  would  seem  muf- 
fled in  a  horrible  pall,  save  just  at  the  points 
where  the  heavenly  bodies  are.  He  would  have 
the  impression  of  not  being  able  to  see  an  inch 
before  him.  He  would  see  sun,  moon,  and  stars 
all  at  the  same  time  ;  but  they  would  look  as  if 
hissing  on  a  sea  of  ink.  The  blackness  would 
seem  solid  enough  to  be  cut  with  a  knife.  An 
Egypt  in  the  sky  would  seem  to  him  to  have  com- 
pletely overrun  its  Spain,  and  indeed  its  whole 
atlas  of  celestial  empires.  And  should  he  try  to 
express  his  feelings,  and  to  say,  "  How  awful  is 
this  blackness  !  "  —  "  How  glorious  are  these  lu- 
minaries !  "  —  no  sound,  nor  specter  of  a  sound, 
could  issue  from  his  shouting  lips. 

Such  is  the  "  House  I  live  in  "  of  the  heavenly 
bodies.  What  are  the  heavenly  bodies  them- 
selves—  what  this  sun,  this  moon,  these  planets 
and  comets  and  fixed  stars  and  nebulas  ? 

In  remotest  times,  very  likely,  men  thought 
them  distant  heavenly  torches,  or  openings 
of  various  sizes  through  the  sky  into  an  ocean  of 
glory  beyond.  In  process  of  time,  they  came  to 
be  very  extensively  regarded  as  intelligent  beings 
—  gods  and  goddesses,  also  human  beings  raised 
to  the  skies  on  account  of  illustrious  merit,  or, 
what  was  not  always  the  same  thing,  the  favor 
of  the  divinities.  The  sun  was  Apollo,  god  of 
fiery  arrows  ;  the  moon  was  Diana,  goddess  of 


44  SECOND    LECTURE. 

the  silver  bow  ;  and  so  on,  until  the  sky  was  one 
great  Parliament  House  of  deities  in  everlasting 
session.  Worship  was  paid  to  the  sinning  crowd  ; 
to  them  incense  rose,  hymns  were  chanted,  and 
victims  bled.  In  civilized  countries  of  modern 
times,  people  are  far  enough  from  such  views  of 
the  nature  of  the  heavenly  bodies :  multitudes  do 
not  even  trouble  themselves  to  have  any  views 
whatever  on  the  subject.  They  have  never  put 
the  question  to  themselves,  "  What  are  they  — 
those  bright  lights  above  us  ? "  Accustomed  to  the 
sight  from  infancy,  busied  in  their  digging  and 
buying  and  selling,  it  has  never  occurred  to  them 
to  be  curious  as  to  the  nature  of  those  far-off 
luminaries.  They  are  content  to  have  the  use 
of  them  —  to  work  by  the  sunlight,  to  walk  by 
the  moonlight,  to  steer,  and  perhaps  to  steal,  by 
the  starlight.  In  this  respect,  they  are  inferior  to 
many  in  the  remotest  and  rudest  ages.  And  yet 
the  question  has  long  been  well  answered,  and 
the  answer  is  in  possession  of  tens  of  thousands 
on  all  sides  of  them.  What  are  the  heavenly 
bodies  !  Not  lamps,  not  apertures  through  which 
glory  shines,  not  personages  ;  but  immense  mass- 
es of  unintelligent  matter,  some  self-luminous, 
and  the  rest  shining  by  reflected  light.  It  is 
found  that  the  light  coming  direcly  from  a  can- 
dle, or  other  sell-luminous  object,  differs  by  a  cer- 
tain property  from  the  same  light  after  it  has 
undergone  reflection.  This  fact  enables  us  to 


NATURE    OF    THE   HEAVENLY  BODIES.       45 

ascertain  easily  that  a  part  of  the  objects  in  the 
sky  shine  by  reflected  light,  while  the  rest  are 
self-luminous.  The  sun,  and  fixed  stars,  and 
nebulae  are  found  to  be  self-luminous  ;  the 
moon,  planets,  comets,  and  zodiacal  light  shine 
only  by  the  light  that  comes  from  these.  If  a 
man  is  confronted  by  what  purports  to  be  a 
ghost,  he  pronounces  it  well-authenticated  flesh 
and  blood  just  as  soon  as  he  sees  that  it  casts  a 
shadow  ;  so,  just  as  soon  as  we  find  that  the 
heavenly  bodies  emit  and  reflect  light,  we  know 
that  they  are  true  matter ;  and,  so  far  as  we 
have  been  able  to  observe  this  matter,  it  has  the 
appearance  of  that  which  composes  our  earth. 
If  the  moon  is  looked  at  through  a  telescope,  we 
see  a  rugged  surface  of  mountains  and  valleys. 
In  regard  to  the  other  bodies  in  the  sky,  the  glass 
does  not  serve  us  as  well ;  but  the  telescopic 
aspect  of  most  of  the  planets  gives  none  the  less 
decidedly  the  impression  of  an  earth-like  surface. 
But  the  heavenly  bodies  are  not  only  masses  of 
earthy  matter  :  they  are  masses  of  immense  size. 
They  look  small  to  us,  it  is  true  —  the  sun  and 
moon  occupying  no  larger  space  in  your  eye  than 
does  the  crown  of  your  hat  at  the  distance  of  a 
few  feet,  and  most  of  the  stars  showing  as  mere 
needle-points.  They  do  look  very  small,  most 
eertainly  ;  but  so  the  great  earth  would  if  we 
should  go  very  far  away  from  it.  The  earth  is 
so  large  that  we  can  travel  upon  it  for  months 


46  SECOND    LECTURE. 

and  years  without  crossing  our  track ;  and  yet, 
should  we  go  off  into  space  from  it,  this  immense 
bulk  would  gradually  lessen  on  the  eye  till  at 
last  it  would  appear  no  larger  than  the  smallest 
star.  Though  the  dog  bays  at  the  moon  as  if 
it  were  within  hearing,  though  the  savage  thinks 
that  he  could  almost  bring  down  the  sun  with  his 
arrow,  though  so  intelligent  a  person  as  Yirgil 
tells  us  of  a  personage  who  brushed  the  stars 
with  his  sublime  head,  yet  it  is  very  easily  dis- 
covered that  the  nearest  of  the  heavenly  bodies 
must  be  thousands  and  thousands  of  miles  away. 
This  is  proved  by  the  fact  that  only  a  few  of  them 
appear  to  change  their  places  on  the  sky  at  all  in 
consequence  of  any  change,  however  great,  in  our 
position,  and  these  few  only  in  a  very  slight  de- 
gree. A  few  steps  will  change  the  place  on  the 
heavens  of  some  near  objects  a  whole  quadrant : 
but  yonder  mountain,  twenty  miles  away  on  the 
horizon,  would  scarcely  seem  to  stir  should  you 
walk  an  hour  perpendicular  to  the  line  of  its 
direction.  Now,  as  to  the  heavenly  bodies,  it  is 
found  that  one  might  travel  thousands  of  miles 
on  the  earth,  without  shifting  the  apparent  place 
of  most  of  them  on  the  vault  in  the  slightest  — 
without  shifting  the  apparent  place  of  any  of 
them,  save  by  a  very  trifling  amount.  So  it  is 
plain  that  they  must  be  at  a  very  great  distance 
from  us.  Why,  if  a  body  were  displaced  on  the 
sky  to  the  amount  of  the  moon's  apparent  diame- 


DISPOSITION    OF   THE    HEAVENLY  BODIES.     47 

ter,  by  our  going  a  thousand  miles  on  the  earth, 
it  must  be  a  hundred  thousand  miles  away  ;  and 
there  is  not  a  body  in  the  whole  heaven  that  would 
undergo  any  thing  like  that  displacement  were 
we  to  remove  such  a  distance.  So  we  must  con- 
clude that  all  the  heavenly  bodies  are  immensely 
remote  from  us,  and  so  of  immense  magnitude. 

How  are  these  great  masses  of  matter  actually 
disposed  in  space  ?  According  to  some  principle  of 
orderly  arrangement,  we  should  presume.  The  Su- 
preme Cause  is,  no  friend  to  confusion.  Still,  what 
the  celestial  order  really  is,  is  not  easily  discover- 
able. There  is,  to  first  view,  no  system  whatever 
in  the  distribution  of  large  portions  of  the  heavenly 
bodies.  It  is  as  if  the  Genius  of  disorder  had  sown 
them.  In  other  parts,  there  are  appearances  of  sys- 
tematic arrangement ;  but  then  the  question  arises, 
Is  the  apparent  arrangement  the  real  one  ?  Can 
I  say  that  two  stars  are  actually  near  each  other 
in  space,  because  they  appear  near  each  other  on 
the  sky  ;  or  that  other  two  stars  are  remote  from 
each  other,  because  one  appears  in  the  east,  while 
the  other  is  seen  in  the  west  ?  Not  as  long  as  I 
find,  that,  by  putting  myself  between  two  trees 
only  ten  feet  apart,  I  project  them  on  directly  op- 
posite points  of  the  heavens  ;  not  as  long  as  I 
find  that  the  tree  which  is  only  ten  feet  from  me, 
falls  on  the  sky  at  the  same  point  with  yonder 
mountain  which  is  twenty  miles  away.  So  there 
was  no  small  difficulty  in  ascertaining  the  real 


48  SECOND    LECTURE. 

plan  among  the  celestial  bodies;  and,  in  fact,  it 
was  not  ascertained  till  after  long  ages  of  obser- 
vation and  study.  But  persuaded,  as  thinking 
men  were,  that  there  must  be  system  everywhere 
within  the  domains  of  the  Supreme  Wisdom ; 
well  aware,  as  most  of  them  were,  that  apparent 
confusion,  from  unfavorable  points  of  view,  often 
covers  a  system  of  exactest  order  —  they  did  not 
give  over  to  inquire.  At  last  they  found  the  fa- 
vorable stand-point  which  laid  open  the  whole 
mystery  of  the  celestial  arrangements.  The  lamps 
of  a  city,  as  one  approaches  it  some  evening,  ap- 
pear a  mere  chaos  of  bright  points  ;  and  yet  that 
city  is  Philadelphia,  where  streets  cut  streets  des- 
perately at  right  angles  and  all  the  lights  gleam 
on  the  sides  of  perfect  squares.  And  they  seem 
so  to  the  same  man,  when,  turned  aeronaut,  his 
balloon  has  shot  him  up  thousands  of  feet  over  the 
centre  of  the  city.  He  has  now  found  the  true 
point  of  view.  An  army  engaged  in  battle  seems 
an  inextricable  maze  to  a  looker-on  from  the  same 
plain  —  men  projected  on  and  crossing  men  till  all 
individual  outlines  are  lost  —  and  yet  here  are  all 
the  parts  of  a  host,  from  corps  to  companies,  each 
under  its  own  leader,  in  unbroken  array  and  ad- 
mirable discipline,  pressing  forward  on  victory  to 
the  rhythm  of  exulting  trumpet  and  drum  as  only 
Napoleon  and  Austerlitz  know  how  to  pour  them 
along.  And  it  seems  so  to  the  same  man  just  as 
soon  as,  arrived  at  yonder  lofty  hill-top,  he  mingles 


DISPOSITION    OF  THE   HEAVENLY  BODIES.  49 

with  the  Emperor's  staff  and  looks  down  on  the 
whole  scene.  He  has  now  the  true  point  of  view. 
So, at  last,  astronomers  have  found  their  true  point 
of  view.  They  look  from  over  the  beaming  city. 
They  gaze  down  on  the  rushing  army.  And  now 
the  whole  celestial  economy  of  arrangement  stands 
unfolded.  What  is  it  ?  The  system  of  arrange- 
ment is  this :  — 

1.  A  body,  not  self-luminous,  has  one  or  more 
like  bodies  revolving  around  it.    There  are  many 
such   systems,  which  we  will   call  satellite -sys- 
tems. 

2.  Several  of  these  primary  systems  form  a  still 
larger  neighborhood,  and  revolve  about  a  self- 
luminous  body,  like  the  sun.     There  are  many 
such  systems,  which  we  will  call  planet-systems. 

3.  Several  of  these  planet-systems  form  a  still 
larger  neighborhood,  and  revolve  about  a  com- 
mon point  within  it.     There  are  many  such  sys- 
tems, which  we  will  call  sun-systems. 

4.  Several  of  these  sun-systems  form  a  neigh- 
borhood still  larger,  and  circulate  about  one  point 
within  it.     There  are  many  such  systems,  which 
we  will  call  group-systems. 

5.  Several  of  these  group-systems  unite  in  a 
still  larger  neighborhood,  and  in  revolving  about 
a  common  point  within  it.    There  are  many  such 
systems,  which  we  will  call  cluster-systems. 

6.  Several  of  these  cluster-systems  combine  into 
ai_rther  system  still  grander,  whose  centre  of  mo- 


50  SECOND    LECTURE. 

tion  is  also  common  to  all  its  members.  There 
are  many  such  systems,  which  we  will  call  ne- 
bula-systems. 

7.  Finally,  all  the  systems  of  space,  composing 
one  great  neighborhood  that  embraces  all  other 
neighborhoods,  revolve  around  one  motion-centre 
of  the  creation.  This  we  will  call  the  universe- 
system. 

You  see  that  it  is  a  wheel  within  a  wheel.  Cer- 
tainly, the  i  height  of  that  last,  all-embracing  wheel 
is  exceeding  dreadful.7  Each  order  of  systems 
includes  all  the  orders  below  it ;  and  each  pri- 
mary system  has  at  least  as  many  revolutions  as 
there  are  different  orders.  It  is  very  like  the  ar- 
rangement of  human  society.  First,  we  have  the 
elementary  group  of  the  family,  revolving  about 
the  home ;  then  several  families,  making  a  town, 
revolving  about  its  central  village ;  then  several 
towns,  making  a  county, revolving  about  its  county 
seat;  then  several  counties, making  a  State, revolv- 
ing about  its  State  capital ;  then  several  States, 
making  a  nation,  revolving  about  the  national 
metropolis  ;  then  several  nations,  making  a  world, 
revolving  about  the  political  centre  of  humanity , 
which  once  was  Rome,  which  now  is  —  shall  we 
say  London  or  Paris  or  St.  Petersburg  or  Wash- 
ington ? 

Take  another  illustration ;  for  it  is  important 
to  have  this  matter  familiar.  In  these  warlike 
times,  it  is  hard  to  resist  dealing  in  warlike  illus- 


DISPOSITION    OF   THE    HEAVENLY  BODIES.     51 

trations :  besides,  it  may  fairly  be  presumed  that 
they  will  be  understood  with  special  facility.  Ima- 
gine the  encampment  of  a  great  army.  On  enter- 
ing it,  the  order  in  which  the  tents  are  disposed 
does  not  readily  appear.  But,  on  examination, 
we  find  that  there  is  a  very  rigid  system  of  ar- 
rangement, and  that  this  is  it,  First,  the  camp  of 
the  company  about  its  captain,  separated  by  a 
plain  interval  from  all  other  company -camps. 
Next,  expanding  around  this,  is  the  camp  of  a 
regiment  about  its  colonel,  separated  by  a  still 
more  marked  interval  from  all  other  regiment- 
camps.  Then,  expanding  around  the  regiment, 
is  the  camp  of  the  brigade  about  its  brigadier, 
separated  by  an  interval  still  more  decided  from 
all  other  brigade -camps.  Further,  expanding 
around  the  brigade,  is  the  camp  of  the  division  or 
corps  about  its  major-general,  separated  by  an 
interval  still  broader  from  all  other  corps-camps. 
Lastly,  expanding  around  the  corps,  is  the  whole 
encampment  of  the  grand  army  about  its  general 
or  marshal  or  monarch.  See  here  a  picture  of 
the  great  encampment  of  the  sky!  I  say  "en- 
campment ; "  for,  to  one  watching  the  sky  for  a 
short  time,  every  thing  seems  stationary.  But, 
really,  the  sky  is  not  a  camp.  It  is  rather  a  glo- 
rious parade  ground,  full  of  motion,  full  of  or- 
derly, systematized  motion  —  a  flaming  bannered 
field  on  which  the  various  celestial  powers  are 
going  through  their  various  related  evolutions 


52  SECOND    LECTURE. 

under  their  respective  leaders  —  companies  of 
stars  maneuvering  under  star -captains  ;  regi- 
ments, brigades,  divisions,  whole  hosts  of  stars, 
manoeuvering  under  star- chiefs  of  as  many  as- 
cending grades  of  rank  and  splendor.  Hail,  host 
of  heaven  !  Hail,  glittering  rank  and  file  !  Hail, 
gorgeous  commanders  in  golden  mail,  and  shin- 
ing far  o'er  the  field  !  Veterans  all,  though  un- 
scarred,  as  far  as  we  can  now  see,  —  all  hail !  for, 
as  we  shall  soon  find,  such  brilliant  equipment, 
such  skillful  commanding,  such  perfect  obeying, 
such  complicate  wheeling  on  exactest  time  and 
admirable  step,  was  never  seen  in  any  terrestrial 
army. 

But  you  would  like  the  evidence  that  such  is 
the  arrangement  of  the  heavenly  bodies.  It  is 
observed  that  every  thing  on  the  earth  is  heavy. 
We  never  take  up  any  thing  about  the  earth, 
whether  great  or  small,  whether  this  sort  of  mat- 
ter or  that,  without  finding  it  to  have  more  or  less 
weight.  That  is  to  say,  the  earth  attracts  it,  or  it 
attracts  the  earth,  or,  perhaps,  both  mutually  at- 
tract. Newton,  on  thinking  the  matter  over  (we 
know  how  it  happened,  under  the  famous  apple- 
tree,  and  how,  as  the  apple  came  down,  the  thought 
of  the  philosopher  went  up),  concluded  to  adopt 
the  last  view,  and  to  suppose  that  an  attractive 
force,  developing  itself  equally  in  all  directions, 
and  extending  to  all  distances,  belongs  to  every 
atom  of  matter,  terrestrial  and  celestial.  On  the 


DISPOSITION    OF   THE   HEAVENLY  BODIES.     53 

basis  of  this  assumption,  he  was  able  to  prove, 
mathematically,  that  every  body  must  attract 
every  other  body  with  a  force  proportioned  di- 
rectly to  its  own  quantity  of  matter,  and  inverse- 
ly to  the  square  of  the  distance  between  the  bodies. 
If  you  double  the  amount  of  matter  in  a  body, 
you  double  its  attractive  force  ;  if  you  double  its 
distance  from  another  body,  you  quarter  its  at- 
tractive force  on  that  body.  With  this  law,  he 
proceeded  to  demonstrate,  by  the  most  rigorous 
of  mathematics,  that,  if  two  or  more  free  bodies 
in  space  form  a  neighborhood,  they  must  instant- 
ly rush  together,  or  they  must  all  revolve  about 
their  common  centre  of  gravity ;  meaning,  by 
this  common  centre,  that  point  among  them 
where  their  several  attractions  just  balance  each 
other,  so  that  a  particle  at  that  point  would  have 
no  tendency  to  move.  The  fact  that  such  bodies 
are  found  apart,  after  an  existence  of  thousands 
of  years,  will  then  be  proof  that  they  are  all  re- 
volving about  their  common  centre  of  gravity. 
Hence,  if  several  celestial  bodies  are  found  con- 
tiguous, as  compared  with  others,  we  must  infer 
that  they  form  a  system  of  revolution  by  them- 
selves ;  if  several  of  these  minor  systems  are 
found  contiguous,  as  compared  with  others,  we 
must  infer  that  they  compose  a  still  larger  revolv- 
ing system ;  and  so  on.  Or,  if  we  find  certain 
heavenly  bodies  forming  together  a  system  of 
revolution,  we  must  infer  their  relative  contiguity 


54  SECOND    LECTURE. 

to  each  other  in  space.  We  need  only  to  estab- 
lish, by  observation,  the  actual  existence  of  either 
such  celestial  neighborhoods  as  have  been  de- 
scribed, or  such  related  motions  as  have  been 
described,  in  order  to  establish  the  existence  of 
both.  Now  we  can  always  do  the  one  or  the 
other. 

But  one  suggests,  "  There  is  an  assumption  at 
the  bottom  of  this  argument.  Newton  assumed 
that  attractive  power,  flowing  out  equally  in  all 
directions  and  at  all  distances,  belongs  to  every 
particle  of  matter,  celestial  as  well  as  terrestrial. 
Where  is  the  proof  that  this  assumption  is  cor- 
rect ?  "  I  answer,  that  we  have  no  other  proof 
than  is  involved  in  the  fact,  that,  after  very  long 
trial,  the  results  flowing  from  the  assumption  have 
not  been  contradicted  by  any  known  fact,  while 
they  wonderfully  harmonize  with  and  explain 
all  the  leading  astronomical  phenomena.  A  man 
compute's,  by  the  law  of  gravity,  just  where  in  the 
sky  a  planet  or  comet  ought  to  be  found  at  a  given 
time ;  and,  when  the  moment  comes,  we  look  at 
the  spot,  and  lo !  the  body  is  there.  Feats  of  this 
kind  have  been  so  numerous ;  the  law  of  gravity 
has  been  tried  for  the  explanation  of  such  hosts 
of  astronomical  facts,  and  with  such  invariable 
and  brilliant  success  —  that  astronomers  have  at 
last  come  to  rely  on  its  truth  with  unbounded 
confidence.  And  they  are  philosophically  obliged 
to  do  so.  The  original  assumption  stands  proved 


DISPOSITION   OF   THE   HEAVENLY  BODIES.     55 

by  an  overwhelming  experience.  It  has  been 
gradually  established  by  an  immense  induction  of 
particulars.  And  now  men  can  not  refuse  confi- 
dence to  it  without  rejecting  that  Baconian  phil- 
osophy which  lies  at  the  foundation  of  all  our 
modern  science. 

That  you  may  still  better  realize  the  weight  of 
this  proof,  let  us  suppose  a  case.  Imagine  an  im- 
mense castle,  with  every  gate  and  door  about  it 
locked.  You  are  informed,  on  authority  that  you 
can  not  question,  that  there  once  existed  a  single 
key  which  could  open  every  room  and  closet  and 
drawer  of  the  edifice  ;  but,  alas  !  it  has  long  been 
lost.  One  day,  in  walking  about  the  premises, 
you  stumble  on  something  that  looks  very  much 
like  a  key,  an  ancient  key,  a  key  that  on  pressure 
of  a  spring  can  be  made  to  take  almost  any  shape. 
Well,  you  can  not  help  your  thoughts  :  they  do  at 
once  suggest  to  you  that,  perhaps,  you  have  been 
fortunate  enough  to  fall  in  with  the  long-lost  won- 
derful bit  of  iron  that  can  let  you  into  every  part 
of  the  sealed  castle.  Still  you  could  be  surer  — 
a  great  deal  surer ;  in  fact,  you  have  very  serious 
fears  lest,  on  trial,  your  key  shall  prove  a  mere 
pretender.  Tremblingly  you  try  it  on  the  court- 
yard gate :  after  some  trouble,  the  gate  flies  open. 
Your  courage  rises.  Eagerly  you  approach  the 
main  entrance,  and  try  that:  after  a  while,  that 
too  gives  way,  and  you  enter  the  castle  proper. 
You  are  now  still  more  sanguine  thaA  your  key  is 


56  SECOND    LECTURE. 

the  true  one.  Still,  it  may  fail  at  the  very  next 
trial.  So  you  proceed  to  question  another  door, 
and  another,  and  still  another  ;  with  continually 
augmenting  confidence"  as  success  follows  success. 
You  find  very  great  difficulty  at  times,  both  in 
adapting  and  turning  the  key ;  you  have  to  de- 
lay before  some  doors  a  long  time ;  but,  in  nearly 
every  case,  success  comes  at  last.  And  now,  on 
counting  up,  you  find  that  your  key  has  opened 
for  you  all  the  main  rooms  in  the  castle  ;  in  fact, 
all  that  you  have  seriously  and  patiently  tried — 
doors  of  oak,  doors  of  iron,  doors  with  locks  of 
the  strangest  and  most  intricate  pattern  —  it  has 
conquered  them  all.  At  length  you  are  perfectly 
satisfied.  You  would  not  give  the  snap  of  your 
.finger  for  any  additional  evidence  that  your  key 
is  the  genuine.  Should  some  one  come  to  you 
and  say,  "  My  dear  sir,  are  you  not  a  little  too 
credulous  —  do  you  not  give  your  faith  in  this  case 
a  little  too  easily  —  as  for  me,  I  am  not  quite 
sure  that  there  is  no  mistake,  am  afraid  you 
have  not  the  true  key  yet ! "  —  you  would  be 
tempted  to  reply,  "  My  very  wise  sir,  when  did 
you  escape  from  the  asylum?"  Such  a  man  is 
beyond  argument. 

Now,  this  is  just  the  case  that  has  been  pre- 
sented to  astronomers.  Here  is  the  immense  sky- 
castle,  that,  from  the  beginning,  has  been  fast 
locked  up  from  men  —  a  huge,  inaccessible,  inhos- 
pitable warrior-monastery.  Men  knew  there  must 


DISPOSITION    OF   THE   HEAVENLY  BODIES.     57 

be  some  clew  to  those  mysterious  cloisters  —  some 
key  or  keys  that  could  match  the  wards  of  those 
innumerable  locks.  Where  was  it?  None  knew. 
It  had  never  been  seen  from  the  beginning.  Did 
the  architect,  as  soon  as  the  magnificent  struc- 
ture was  finished  and  carefully  locked  up,  like 
the  God  of  the  "Night  Thoughts,"  fling  the  key 
from  the  starred  battlements  far  into  the  pitchy 
and  bottomless  abyss  of  space  ?  But  no,  this 
could  not  be ;  and  so  men  went  to  roaming  about 
the  purlieus  of  the  heavens,  looking  for  that  lost 
Pleiad  of  a  key ;  and  oh,  how  often,  mean- 
while, did  they  throw  longing,  not  to  say  despair- 
ing, glances  at  that  stern,  unrelaxing  sky  where 
such  treasures  of  science  were  keeping  eternal 
quarantine  1  At  last  Newton,  one  of  these  seek- 
ers, stumbled  on  the  law  of  gravity.  Is  this  the 
key  ?  It  has  the  look  of  one  ;  for  it  is  seen  at 
once  to  harmonize  and  explain  many  terrestrial 
facts.  It  looks  like  a  multiple  key ;  for  it  is  won- 
derful what  a  variety  of  great  theorems  may  be 
drawn  out  of  this  same  law  of  gravity.  As  it 
were,  you  have  but  to  press  a  spring  to  make  it 
assume  an  almost  endless  variety  of  forms.  So 
Newton's  heart  fluttered  with  hope  —  mere  hope. 
Tremblingly  he  put  his  key  to  the  test.  What 
:  was  his  joy  to  hear  that  first  ponderous  bolt  fall 
back?  Success  followed  success;  courage  swelled 
on  courage.  Newton  himself  lived  long  enough 
to  unlock  several  of  the  main  gates  of  the  heavens 


58  SECOND  LECTURE. 

with  his  own  bands.  Encouraged  by  his  success, 
many  other  strong  and  skillful  hands  grasped  the 
victorious  law  of  gravity  and  essay edP  other  en- 
trances,— sometimes  succeeding  easily,  and  some- 
times with  no  small  difficulty  and  delay,  but  nearly 
always  succeeding.  So  it  has  gone  on  up  to  the 
present  time  —  door  after  door  opening  —  doors 
of  oak,  doors  of  iron,  doors  of  brass,  doors  of  gold, 
doors  of  the  strongest  look  and  lock-pattern,  doors 
by  scores  and  hundreds — they  have  gone  on  yield- 
ing, one  after  another,  to  the  wondrous  key,  till 
now  we  may  speak  of  the  Open  Heavens.  "What, 
Earth  and  Moon  open  !  Have  you  unlocked  their 
hundred -gated  theory?"  Yes:  not  a  consider- 
able gate  of  that  Thebes  but  has  described  a  com- 
plete semi-circle.  "  What,  Sun  and  Planets  open  ! 
Has  your  key  of  gravity  set  their  thousand  gates 
a  swinging  ?  "  Yes,  swinging  to  their  full  capa- 
city—  thanks  to  the  dexterous  and  patient  hand- 
ling of  wedded  observation  and  geometry.  "  What, 
Star  Groups  open  !  They  have  a  myriad  of  strange 
and  ponderous  gates ;  and  have  even  these  yield- 
ed? "  Ask  the  Herschels  and  Souths  and  Bessels. 
Yes :  even  those  wards  are  not  too  intricate  to  be 
traversed  by  the  victorious  tenons  and  tongues  of 
the  law  of  gravity ;  and  now,  if  you  choose,  you 
can  step  over  the  golden  threshold  of  many  a 
planetary  sun,  and  see  for  yourselves  the  marvels 
within.  "  What,  Clusters  open  !  What  Nebulae 
open  !  And  now  I  say.  Hail  to  the  law  of  grav- 


DISPOSITION  OF  THE  HEAVENLY  BODIES.     59 

it/,  if  it  can  fling  open  to  the  gazing  science  of 
men  those  million-gated  and  doubly -locked  re- 
gions !  Can  it,  indeed,  do  that  topmost  feat  ?  " 
Ask  the  Struves  and  Peters  and  Argelanders 
and  Msedlers ;  and  have  not  we  ourselves  heard, 
with  our  own  ears,  the  recoil -thunder  of  some 
bolts  under  the  strong  hands  of  these  giants? 
Yes  :  I  have  myself  seen  some  of  those  burnished 
gates  shot  back  to  the  very  wall,  and  the  philoso- 
phers who  accomplished  the  feat  yet  standing, 
key  in  hand,  with  flushed  faces,  gazing  into  the 
aiidience  chamber  and  royal  pavilions  of  that 
highest  heaven  of  matter.  God  bless  the  key  i 
It  is  GENUINE. 


III. 
SATELLITE    SYSTEMS. 


III.    SATELLITE  SYSTEMS. 

EXAMPLE  —  EARTH  AND  MOON. 

1.  DIURNAL  REVOLUTIONS 66 

2.  MUTUAL  DISTANCE 7o 

3.  SHAPES  AND   SIZES .        .  71 

4.  MUTUAL  GRAVITATIONS 77 

5.  MASSES  AND  DENSITIES 81 

6.  ORBITS 84 

7.  MUTUAL  ASPECTS .87 


Library, 


THIRD    LECTURE. 


SATELLITE   SYSTEMS. 

IN  the  last  lecture  I  stated  how  the  Heavenly 
Bodies  are  arranged  in  space.  They  are  dis- 
tributed into  neighborhood  systems  of  at  least 
seven  orders.  These  are  the  Satellite  Systems, 
the  Planet  Systems,  the  Sun  Systems,  the 
Group  Systems,  the  Cluster  Systems,  the  Nebula 
Systems,  the  Universe  System.  Each  order  of 
systems  includes  all  the  orders  below  it ;  and  the 
members  of  each  system  revolve  about  its  center 
of  gravity.  I  will  now  proceed  to  prove  and  in- 
terpret these  systems  in  the  order  named. 

A  Satellite  System  consists  of  two  or  more  con- 
tiguous heavenly  bodies  which  are  not  self-lumi- 
nous, and  which  revolve  about  their  common  cen- 
ter of  gravity.  There  are  many  such  systems  ;  but 
the  most  accessible  and  useful  example  which  I 
am  able  to  present  is  that  of  the  earth  and  moon. 

It  was  long  before  men  were  prepared  to  reckon 
the  earth  among  the  heavenly  bodies.  It  seemed 
at  first  view  so  different  from  them  —  so  uhshin- 

63 


64  THIRD    LECTURE. 

ing,  so  like  an  indefinitely  extended  plain  with 
solid  foundations  of  endless  depth.  But  further 
thought  corrected  this  mistake.  Whence  come 
the  sun  and  stars  as  they  rise  in  the  east,  and 
whither  go  they  as  they  set  in  the  west  ?  It  is 
clear  that  they  pass,  on  the  average,  twelve  hours 
out  of  the  twenty-four  under  the  earth.  So  the 
earth  is  really  a  body  of  finite  though  great  ex- 
tent, lying  loose  in  space  —  space  under  it,  space 
over  it,  space  all  around  it.  Of  course  it  must 
be  so.  As  to  the  notion  that  the  earth  does  not 
shine  like  the  distant  heavenly  bodies,  it  is  quite 
without  foundation.  Our  world  does  not  appear 
as  brilliant,  simply  because  we  do  not  see  it  from 
out  of  the  midst  of  the  night  as  we  do  the  moon 
and  stars.  They  do  not  appear  bright  by  day 
—  for  the  most  part  do  not  appear  at  all  —  it  is 
only  when  they  are  in  the  light  while  we  are  in 
the  dark,  that  they  seem  to  us  to  shine.  If,  some 
evening,  when  your  room  is  brilliantly  lighted, 
you  take  your  stand  in  the  middle  of  it  and  try 
to  look  out  into  the  street,  you  can  see  nothing  ; 
but  persons  passing  can  see  you  and  all  your 
movements.  To  them  you  shine.  And  could 
we  take  ourselves  away  into  that  pitchy  space 
that  expands  around  us,  till  the  earth  should  ap- 
pear no  larger  than  the  moon,  it  would  appear  as 
bright  as  that  luminary. 

The  earth  shines  like  a  star.     It  shines,  Low- 
ever,  only  by  reflection.     Just  as  soon  as  the 


SATELLITE   SYSTEMS.  65 

light  of  the  other  heavenly  bodies  is  shut  off  from 
any  part  of  its  surface  that  part  becomes  dark. 
In  this  respect  the  moon  is  like  it.  We  notice 
that  it  is  only  that  side  of  the  moon  that  is  toward 
the  sun  that  is  bright ;  and  so  it  happens  that  for 
the  greater  part  of  the  time  the  great  light  that 
rules  the  night  appears  to  us  under  a  broken 
circle.  Also,  the  fact  already  referred  to,  viz., 
that  reflected  light  has  a  different  property  from 
that  which  comes  to  us  directly,  enables  us  to 
pronounce  the  moon  a  mere  reflector.  So  neither 
the  earth  nor  moon  is  self-luminous.  They  fulfill 
the  first  condition  of  a  satellite  system. 

Do  they  fulfill  the  second  condition  ?  Are  they 
contiguous  to  each  other  as  compared  with  other 
heavenly  bodies  ?  If  so,  the  law  of  gravity  proves 
that  they  both  revolve  about  their  common  center 
of  gravity.  Now  this  matter  of  neighborhood  is 
easily  settled.  Ask  whether  any  other  heavenly 
body  shifts  its  place  on  the  sky  any  thing  like  as 
much  as  the  moon,  in  consequence  of  a  given 
change  in  our  place.  By  going  four  thousand 
miles  on  the  earth  we  change  the  moon's  place 
by  about  twice  its  apparent  diameter.  No  other 
body  in  the  heavens  experiences  the  hundredth 
part  of  this  change.  The  earth  and  moon,  there- 
fore, form  a  neighborhood.  Hence  they  must  re- 
volve about  their  center  of  gravity.  And  being 
both  heavenly  bodies,  shining  by  reflected  light, 
they  make  a  satellite  system. 


66  THIRD    LECTURE. 

Now  let  us  notice  the  chief  facts  which  have 
been  ascertained  concerning  this  primary  system. 
And,  first,  each  member  is  found  to  turn  around 
on  itself.  What  makes  the  stars  rise  in  the  east, 
-move  uniformly  across  the  sky  in  parallel  lines 
without  disturbance  of  their  mutual  positions,  set 
in  the  west,  and,  at  the  end  of  twenty-four  hours, 
appear  in  the  east  again  ?  The  most  simple  ex- 
planation is  that  the  earth  turns  around  on  one 
of  its  diameters  from  west  to  east,  with  a  uniform 
motion,  once  in  twenty-four  hours,  while  we  are 
held  to  its  surface  by  the  attraction  of  gravitation. 
Indeed  no  other  explanation  is  admissible.  The 
idea  that  we  are  the  center  of  creation,  and  that 
all  the  host  of  heaven,  at  as  many  different  and 
immense  distances,  have  their  motions  so  adjusted 
to  each  other  as  to  make  the  circuit  of  the  earth 
in  exactly  the  same  time,  is  altogether  too  cum- 
brous to  suit  either  philosophers  or  practical  men. 
Besides,  such  a  system  is  irreconcilable  with  the 
law  of  gravity.  If  it  is  in  the  nature  of  things 
possible  that  the  earth  is  the  center  of  the  uni- 
verse, it  is  not  possible  that  all  the  heavenly  bodies 
should  so  fly  in  the  face  of  gravity  as  to  revolve 
about  this  center  —  or  rather  an  axis  passing 
through  it  —  in  parallel  circles,  in  precisely  the 
same  time  or  in  any  times.  So  we  are  bound  to 
conclude  that  the  earth  moves  about  an  axis 
within  itself,  and  thus  gives  us  the  beneficent  al- 
ternation of  day  and  night. 


REVOLUTIONS,  67 

But  why  are  we  not  sensible  of  this  motion  ? 
How  is  it  possible  that  we  can  be  whirled  around 
so  fast  as  the  rotation  of  so  large  a  body  implies, 
and  be  a  good  part  of  the  time,  as  people  say, 
standing  on  our  heads,  and  yet  remain  entirely 
uninformed  by  our  senses  of  what  is  going  on? 
Why,  every  thing  about  us  shares  our  motion ; 
even  the  atmosphere  goes  around  as  fast  as  we 
do;  there  is  no  jolt  nor  jar  —  how  should  we 
know,  except  by  seeing  objects  moving  by  us, 
that  we  are  in  motion,  any  more  than  does  the 
man  engaged  in  the  fairest  summer  sailing  ? 
Were  he  to  shut  his  eyes,  there  is  nothing  in  his 
sensations  to  show  him  that  he  is  gliding  along : 
were  he  to  open  them  only  on  the  yacht  and  its 
furnishings  he  would  seem  at  rest :  he  must  look 
away  to  the  shore,  and  see  the  trees  and  houses 
slipping  by.  So  we  are  rolled  around  the  world 
so  smoothly  and  equably  that  we  have  to  look 
away  to  the  stars  to  know  that  we  are  rolling  at 
all.  Noiselessly,  without  hitches,  without  tremors 
-  it  is  the  perfection  of  lubricated  and  luxurious 
progress  !  The  softest,  downiest,  springiest  char- 
iot that  ever  went  rolling  over  its  McAdam,  with 
a  prince  inside,  is  an  earthquake  compared  with 
this  natural  omnibus  in  which  we  have  taken 
passage.  As  to  the  prejudice  which  some  persons 
feel  against  having  their  heads  point  in  diametri- 
cally opposite  directions  at  different  hours  of  the 
day,  I  do  not  know  what  can  be  done  for  their 


68  THIRD    LECTURE. 

relief,  unless  it  be  to  assure  them  that  they  shall 
have  the  privilege,  during  their  daily  somer- 
saults, of  always  pressing  their  feet  against  the 
ground  and  holding  their  heads  aloft  in  the 
air. 

A  single  evening's  Etching  of  the  stars  is 
enough  to  show  us  that  the  axis  of  the  earth 
points  nearly  at  the  North  Star ;  that  the  motion 
around  it  is  easterly ;  that  it  is  a  perfectly  uni- 
form motion,  just  the  same  distance  being  made 
in  the  same  time.  So  much  a  single  evening  can 
show  us.  But  it  would  take  a  great  many  even- 
ings to  show  us  another  striking  fact,  none  the 
less  sure,  viz.,  that  the  axial  revolution  is  always 
accomplished  in  exactly  the  same  time.  It  is  on 
evidence  that  our  day  has  not  varied  the  hun- 
dredth part  of  a  second  for  two  thousand  years. 
There  has  not  been  the  slightest  change  within  the 
long  sweep  of  history  and  tradition.  We  must, 
however,  allow  one  or  two  exceptions.  "  Sun 
stand  thou  still  on  Gibeon,  and  thou  Moon  in  the 
valley  of  Ajalon !  So  the  sun  stood  still  in  the 
midst  of  heaven,  and  hasted  not  to  go  down  about 
a  whole  day."  The  Chinese  have  a  tradition  that 
there  was  once  a  day  of  double  the  usual  length. 
And  the  Greeks  have  a  fable  that  may  refer  to 
the  same  thing  —  that  the  son  of  the  Sun  once 
persuaded  his  father  to  allow  him  to  drive  his 
fiery  chariot  for  a  day.  The  result  was  that  such 
another  Phaetonizing  never  took  place.  The  met- 


DIURNAL    REVOLUTIONS.  69 

tlesome  steeds  ran  away  with  the  youth  ;  wan- 
dered up  and  down  the  sky,  setting  every  thing 
in  a  blaze  ;  and  did  not  reach  the  gates  of  the 
west  —  how  could  they  —  till  a  long  time  after 
they  were  due.  So  there  has  been  a  day  of  ex- 
traordinary length.  The  Bible-miracle,  however, 
may  have  consisted,  not  in  suspending  the  mo- 
tion of  the  earth  on  its  axis,  but  in  simply  bend- 
ing the  rays  of  light  from  the  sun  and  moon  so 
as  to  continue  the  illumination,  apparently  from 
the  same  points  of  the  sky,  long  after  the  bodies 
themselves  had  passed  at  their  usual  pace  below 
thft  horizon.  Certainly,  one  or  two  miracles 
aside,  the  length  of  our  day  has  never  changed 
by  the  breadth  of  a  hair :  the  earth  wheels  about 
on  its  axis  now  in  just  the  same  period  as  at  the 
creation.  So  we  have  a  beautiful  unit  of  time  to 
carry  along  with  us  in  our  terrestrial  journeys, 
though  altogether  too  small  for  journeys  astro- 
nomical. 

On  looking  at  the  moon,  to  find  whether  it  also 
turns  around  on  itself,  first  appearances  are 
against  it.  Bring  a  telescope  to  bear  on  its  face. 
We  can  see  many  striking  objects,  but  no  consid- 
erable movement  among  them.  In  case  of  a  ro- 
tation we  ought  to  see  all  such  objects  moving 
across  the  disc  in  parallel  lines.  But,  instead  of 
this,  we  find  them  substantially  stationary. 
Strange  to  say,  this  very  fact,  which  at  first  view 
seems  conclusive  against  a  rotation,  is  the  very 


70  THIRD    LECTURE. 

fact  which  establishes  it.  For,  on  second  thought, 
you  perceive  that  in  case  the  moon  does  not  turn 
on  itself,  whether  we  move  around  it  or  it  moves 
around  us,  we  ought  in  the  course  of  a  revolution 
to  see  it  on  different  sides.  The  fact  that  we  see 
but  one  side  can  only  be  accounted  for  by  suppo- 
sing that  the  body  turns  around  on  one  of  its  own 
diameters,  just  as  fast  as  the  other  revolution  is 
made,  in  the  same  direction  and  nearly  in  the 
same  plane.  We  shall  soon  see  that  this  revolu- 
tion consumes  about  twenty-seven  days.  This, 
then,  is  the  time  in  which  the  moon  turns  com- 
pletely around  on  its  axis.  This  is  the  moon's 
day.  Its  day  and  month  are  of  the  same  length. 
I  have  said  that  the  moon  is  greatly  more 
displaced  on  the  sky  by  a  change  in  our  place  on 
the  earth  than  is  any  other  heavenly  body. 
Hence  I  inferred  that  it  must  be  greatly  nearer 
to  us.  But  that  is  not  saying  that  it  is  very  near  ; 
indeed,  it  is  not  saying  but  that  it  is  a  matter 
of  some  millions  of  miles  away.  The  fact  is,  that, 
though  a  neighbor,  the  moon  is  a  very  remote 
neighbor ;  at  least,  according  to  such  standards  of 
distance  as  we  use  in  our  every-day  affairs.  But 
we  must  hasten  to  enlarge  our  common  units 
both  of  space  and  time.  Astronomical  systems, 
we  shall  find,  are  laid  out  on  a  different  scale 
from  the  neighborhoods  of  this  world  ;  and  miles 
and  days  make  but  a  sorry  figure  in  attempting 
to  deal  with  the  smallest  of  the  mighty  parishes 


DISTANCE   BETWEEN    THE    TWO    BODIES.      71 

of  the  sky.  The  moon  is  240,000  miles  away. 
And  this  is  a  very  close  astronomical  neighbor- 
hood ;  though  hardly  close  enough  to  enable  us 
to  act  the  part  of  the  good  Samaritan  to  our 
neighbor,  in  case  it  should  fall  among  thieves  ; 
though  hardly  putting  it  within  visiting  distance, 
except  for  our  thoughts,  which  have  both  the 
taste  and  the  faculty  for  riding  on  beams  of  light 
and  the  Pegasus  of  poets.  I  say  240,000  miles, 
on  the  average,  and  in  round  numbers.  One 
French  astronomer,  La  Lande1,  goes  to  Berlin,  in 
Prussia ;  another,  La  Caille,  goes  to  the  Cape  of 
Good  Hope.  One  marks  where  he  projects  the 
moon  on  the  sky  at  a  given  moment ;  the  other 
where  he  projects  it  at  the  same.  They  compare 
notes.  Difference  between  the  two  projections 
found  to  be  so  many  minutes  and  seconds.  How 
far  apart  are  the  two  stations  ?  So  many  degrees 
of  latitude,  and  so  many  miles  in  a  straight  line. 
Nothing  more  necessary  than  to  sit  down,  and  by 
a  simple  calculation  in  triangles  which  any  child 
well  advanced  in  his  arithmetic  can  perform,  find 
the  distance  of  the  moon  from  the  earth's  center. 
The  exact  mean  distance  is  found  to  be  238,545 
miles. 

Now  let  us  turn  our  attention  to  the  shapes 
and  sizes  of  the  members  of  this  satellite  system. 
And,  first,  each  member  has  been  found  to  be  a 
round  body,  slightly  flattened  on  two  opposite 
sides.  A  rubber  ball  slightly  compressed  between 


72  THIRD  LECTURE. 

your  two  palms  will  represent  the  figure.  How 
round  the  sky  looks !  Whoever  has  been  at  sea 
has  noticed  that  the  topmasts  of  ship?  are  seen 
first,  from  whatever  quarter  they  may  come. 
Look  at  the  drops  of  rain ;  the  beads  of  dew  with 
which  the  spider-thread  is  strung,  or  which  start 
from  the  brows  of  labor  and  terror ;  the  round 
shot,  which,  when  a  moment  ago  they  left  the  top 
of  the  shot-tower,  were  one  irregular  mass  of 
molten  metal.  Newton  has  proved  mathemati- 
cally, that  the  particles  .of  a  body,  if  free  to  move 
under  the  influence  of  gravity,  must  always  ar- 
range themselves  in  a  globular  shape.  Now  ge- 
ologists tell  us  that  the  particles  which  compose 
the  earth  were  once  in  this  free  state ;  that  far 
back,  before  man's  day,  the  entire  solid,  rocky 
world  was  in  a  state  of  fusion.  We  should  there- 
fore expect  to  find  it  of  a  rounded  figure.  More 
than  this.  The  earth  revolves  on  an  axis.  The 
necessary  effect  of  this  rotation  on  a  fluid  mass 
would  be  to  draw  it  in  at  the  extremities  of  the 
axis  —  the  poles  so  called ;  and  puff  it  out  midway 
between  these  points  —  that  is  to  say,  at  the  equa- 
tor. But  we  are  not  left  to  this  reasoning. 
Have  not  men  sailed  around  the  world  by  sailing 
always  in  one  general  direction,  and  without 
being  sensible  of  any  abrupt  change  of  level  ?  It 
has  been  proved  that  the  attraction  of  a  round 
body  on  objects  external  to  it  is  as  if  all  its  atoms 
were  concentrated  into  one  at  its  center.  This 


SHAPES  AND  SIZES  OF  THE  TWO  BODIES.   73 

being  so,  if  one  would  be  nearer  the  center  of  the 
earth  when  at  its  pole  than  when  at  its  equator, 
bodies  ought  to  fall  more  rapidly  as  we  pass  from 
the  one  toward  the  other.  They  are  found  to 
do  so.  A  pendulum  descends  with  increasing 
speed  as  we  increase  our  latitude  ;  and  it  has 
been  found  that  the  rate  of  increase  in  the  motion 
is  such  that  the  pole  must  be  nearer  the  center  of 
the  earth  than  the  equator  is,  by  a  six-hundredth 
of  an  equatorial  diameter. 

Now  the  moon  is  just  another  such  body  — 
rounded,  but  not  a  perfect  globe.  At  the  full,  its 
disc  appears  as  a  complete  circle ;  and  its  apparent 
shape  at  other  times  —  as  crescent,  half-moon,  gib- 
bous—  can  only  be  accounted  for  on  the  supposi- 
tion that  it  exposes  a  globular  surface  to  the  rays 
of  the  sun.  And,  as  it  revolves  about  one  of  its 
own  diameters,  we  conclude  from  analogy  as  well 
as  from  the  demonstrated  tendency  of  the  atoms 
of  all  rotating  bodies,  that  it  is  slightly  flattened 
at  the  poles. 

Almost  every  one  has  himself  moved  about  on 
the  earth  enough  to  satisfy  him  that  it  is  a  very 
large  body.  The  man  who  has  sailed  around  it, 
and  at  the  end  of  his  two  or  three  years  of  voy- 
age finds  himself  where  he  started,  does  not  need 
to  consult  his  log-book  to  know  that  its  circumfer- 
ence must  be  some  thousands  of  miles.  But 
this  knowledge  is  far  too  vague.  So  we  will 
make  a  still  further  approximation.  Find  a  level 


74  THIRD  LECTURE. 

region,  and  then  measure  due  north  or  south  on 
it  till  you  have  changed  your  latitude  one  degree. 
This  measure  multiplied  by  three  hundred  and 
sixty  gives  you  the  true  circumference  of  the 
earth,  supposing  that  circumference  to  be  strictly 
circular.  The  result  is  about  twenty-five  thou- 
sand miles.  This  is  a  close  approximation  ;  for, 
after  all,  the  earth  differs  but  very  little  from 
a  perfect  sphere.  Still  astronomers  are  not  con- 
tent. They  know  the  body  is  not  an  exact 
sphere.  They  have  a  sort  of  constitutional  weak- 
ness for  the  last  degree  of  accuracy  —  they  must 
hunt  down,  if  possible,  the  ten-thousandth  part 
of  a  mile  in  favor  of  both  equatorial  and  po- 
lar diameter.  And,  indeed,  it  was  a  matter  of 
such  great  practical  consequence  to  know  these 
elements  with  minute  precision  that  Governments 
stepped  in  with  their  vast  resources  to  help  mea- 
sure them.  Coalitions  in  behalf  of  the  balance 
of  power  became,  for  the  time,  coalitions  in  behalf 
of  astronomy.  For  the  time,  jealous  and  hostile 
powers  resolved  themselves  into  a  Committee  of 
the  Whole  on  the  diameter  of  the  earth.  Nations 
took  stock  in  degrees  of  latitude  as  people  lately 
did  in  petroleum.  "  Select  your  men  and  instru- 
ments," said  some  six  or  eight  Governments  to 
men  of  science,  "  and  we  will  pay  expenses."  So 
the  work  was  put  into  choicest  hands ;  the  choicest 
instruments  were  gathered  ;  and  the  illustrious 
laborers  bent  themselves  to  their  task  with  the 


SIIAPEb  AND  SIZES  OF  THE   TWO  BODIES.    75 

determination  to  spare  neither  time,  nor  pains, 
nor  expense,  to  secure  the  most  reliable  results. 
Their  object  was  the  same  as  in  the  case  just  sup- 
posed. It  was  to  measure  lines  running  due 
north  or  south  on  the  earth  —  only  they  would 
measure  very  long  lines,  very  many  of  them,  and 
in  as  widely  differing  latitudes  as  possible.  Thus 
they  would  get  a  choice  average  length  of  a  de- 
gree of  latitude,  and  also  settle  with  great  preci- 
sion its  rate  of  increase  as  we  go  from  the  equator 
toward  the  poles.  But  it  is  hard  to  find  level  dis- 
tricts of  great  length  on  due  north  and  south 
lines.  So  they  determined  to  follow  the  level  re- 
gions in  whatever  direction  they  ran,  and  indeed, 
on  occasion,  forsake  them  altogether  ;  and  after- 
ward reduce  their  zigzag  measurements  to  the 
meridian  and  sea-level,  by  means  of  triangles  and 
levels.  And  so  they  did.  They  wove  a  network 
of  triangles  across  large  tracts  of  country  in  vari- 
ous parts  of  the  world.  They  went  stooping 
along  the  dead  plains,  chain  in  hand,  for  their 
base  lines  ;  they  went  spying  from  hill-top  to  hill- 
top, and  from  beacon  to  beacon,  with  their  theod- 
olites and  circles  —  as  our  own  Coast  Survey 
Commission  were  seen  doing  in  this  neighborhood 
some  years  ago,  and  as  they  have  been  doing  on 
other  parts  of  our  mighty  coast  as  fast  as  the 
mighty  war  would  suffer  them.  International 
triangles  united  countries  as  international  rail- 
roads do  now.  Let  France  hold  up  this  angle, 


76  THIRD  LECTURE. 

Spain  that,  Italy  the  other  !  No  climate  was  too 
hot,  none  too  cold,  for  these  zealous  workers.  Trig- 
onometries could  stand  any  climate  —  why  should 
not  Clairaut  and  Godin  ?  So  forward,  ye  pil- 
grim geometers  !  Spread  out  your  triangles 
along  the  plains !  Hang  them  from  the  tops  of 
mountains  !  Float  them  along  the  seas  !  Stretch 
them  across  the  sands  of  the  desert!  Shadow 
them  with  jungles  and  palms,  and  blister  them 
with  vertical  suns !  Anchor  them  to  icebergs,  and 
bury  them  in  eternal  snows  !  And  so  they  hardi- 
ly and  audaciously  did.  A  line  of  16°  of  latitude 
was  measured  in  India,  of  12°  in  Prance,  of  4°  in 
England,  of  3°  in  Russia,  of  3°  in  Peru,  of  2°  in 
Italy,  of  1°  each  in  Sweden,  Lapland,  Africa,  Unit- 
ed States  —  indeed,  twenty  independent  measure- 
ments in  all.  The  results  obtained  from  a  com- 
bination of  these  were  7,925.648  miles  for  the 
equatorial  diameter,  and  7,899.170  for  the  polar. 
The  old  magicians  drew  circles  ;  these  new  ma- 
gicians drew  triangles.  The  former  were  sup- 
posed to  get  wondrous  results  out  of  their  figures, 
drawn  with  many  a  muttered  hard  word  and 
strange  gesture  —  what  will  these  philosophers 
get  with  their,  words  as  hard,  and  pointings  as 
mysterious,  and  figures  as  uncouth?  Nothing, 
my  friend,  nothing  but  the  diameter  of  the  earth 
in  good  British  statute  miles  and  thousandths  of 
a  mile  —  which,  however,  happens  to  be  worth 
more  than  all  the  work  done  by  all  the  magicians, 


MUTUAL   GRAVITATIONS.  77 

astrologers,  and  soothsayers,  from  the  days  of  Be- 
rosus  downward. 

The  moon  can  not  boast  such  great  dimensions 
as  the  earth.  Still  it  is  wonderfully  larger  than 
it  looks.  It  looks,  say,  a  foot  in  diameter  ;  it 
really  is  eleven  million  times  that.  It  is  plain  that 
can  not  be  a  small  body  which,  on  being  carried 
away  from  us  240,000  miles,  appears  as  large  as 
the  moon.  But  this  is  altogether  too  vague  in- 
formation to  content  astronomers  —  astronomers 
who  want  to  split  a  second  into  one  thousand 
parts,  and  an  inch  into  200,000.  "  What  is  the 
exact  length  of  the  diameter  in  miles  and  small- 
est possible  fractions  of  a  mile  ?  "  demand  they. 
And  they  answer  themselves  in  this  way.  Sup- 
pose two  lines  drawn  from  the  earth's  center  to 
opposite  sides  of  the  moon  ;  then  the  real  diame- 
ter of  the  moon  makes  with  these  a  triangle. 
Now  measure  the  moon's  apparent  diameter, 
which  is  the  angle  included  between  the  supposed 
lines.  The  lines  are  about  240,000  miles  each  ; 
the  angle  is  about  31'.  Then  the  simplest  sort 
of  mathematics  gives  you  two  thousand  one 
hundred  and  sixty  miles  for  the  required  diam- 
eter. 

Though  the  moon  is  so  small  a  body  compared 
with  the  earth,  and  withal  so  remote  from  us,  it  is 
able  to  produce  on  us  some  very  remarkable  effects. 
Most  certainly  I  do  not  here  refer  to  its  supposed 
bearing  en  the  weather,  on  the  complexion,  on 


78  THIRD  LECTURE. 

the  health,  on  the  mind  in  producing  or  modify- 
ing insanity,  on  the  proper  times  for  planting, 
reaping,  felling  timber,  killing  of  domestic  ani- 
mals. Though  the  impression  was  once  almost 
universal,  and  is  still  exceedingly  prevalent,  that 
the  moon  is  a  powerful  and  controlling  agent  in 
these  and  such  particulars,  still  we  must  admit 
that  it  is  an  altogether  erroneous  impression. 
This  has  been  very  satisfactorily  established  by 
the  extended  observations  and  experiments  of 
several  European  philosophers,  and  especially  of 
the  illustrious  Arago.  No  :  I  refer  to  quite  a  dif- 
ferent class  of  phenomena.  And,  first,  the  moon 
takes  hold  of  that  protuberant  equator  of  ours, 
as  if  it  were  a  mere  convenience  for  wrestling, 
and  pulls  and  twists  it  about  after  itself,  making 
the  pole  describe  a  wavy,  nodding  circle  of  some 
46°  diameter  through  the  sky  —  a  little  more  than 
the  hight  of  the  North  Star  above  our  horizon. 
This  effect  is  due  partly  to  the  sun  ;  but  the  moon 
is  the  chief  agent.  For  long  periods,  however, 
this  motion  of  the  pole  would  not  be  noticed  by 
common  observers ;  it  is  so  exceedingly  slow, 
requiring  about  twenty-six  thousand  years  to 
make  an  entire  revolution.  In  consequence  of 
it,  the  axis  of  the  earth  which  now  points  nearly 
at  the  North  Star,  will,  after  pointing  a  little 
nearer  to  it,  gradually  recede,  and  twelve  thou- 
sand years  hence  point  40°  away  from  it ;  and 
then  the  bright  star  Lyra  will  be  the  pole-star. 


MUTUAL   GRAVITATIONS.  79 

Let  the  men  of  the  year  13,860  look  in  the  north- 
west for  their  north. 

Another  more  noticeable  effect  of  the  moon's 
attraction  are  the  tides.  Twice  a  day  the  earth, 
like  every  good  man,  attempts  communion  with 
the  sky.  Twice  a  day  the  bosom  of  the  seas  swells 
heavenward.  The  explanation  is  this.  As  the 
earth,  in  revolving  on  its  axis,  presents  all  parts 
of  its  surface  in  succession  to  the  moon,  that 
body,  by  the  attraction  of  gravitation,  draws  up 
the  water  in  a  ridge  toward  itself,  at  the  same 
time  making  a  similar  ridge  by  drawing  the  earth 
away  from  the  water  on  the  opposite  side :  so  that 
we  have  two  great  tidal  swells,  convex  toward  the 
west,  about  twelve  hours  apart,  apparently  follow- 
ing the  moon  in  its  daily  movement  around  the 
earth ;  checked  somewhat  in  their  movement  by 
their  own  inertia  and  friction  among  the  barriers 
of  shores  and  irregularities  of  sea-beds  ;  re- 
flected in  this  direction  and  that,  according  to  the 
lay  and  shape  of  coasts ;  about  two  and  a  half 
feet  high  on  the  average,  but  heaped  up  as  high  as 
fifty  or  even  one  hundred  and  twenty  feet  in 
some  confined  places  of  peculiar  conformation, 
and  then  almost  or  quite  dissipated  by  shoals  and 
other  dispersive  agencies.  Thus  it  would  seem 
to  a  bird's-eye  view.  But  really  there  is  no  pro- 
gressive movement  of  the  water  in  the  open  sea 
in  the  case  of  the  tides.  No  European  water  is 
rolled  over  to  America  at  the  rate  of  a  thou- 


80  THIRD  LECTURE. 

sand  miles  an  hour.  It  is  merely  a  successive 
rising  and  sinking  of  the  sea  all  round  the  world. 
The  effect  is  owing  in  part  to  the  attraction  of  the 
sun  ;  but  the  moon  is  the  chief  agent.  When  the 
sun  and  moon  act  in  the  same  line,  or  nearly  so, 
—  at  the  times  of  new  and  full  moon —  the  tide- 
swell  is  considerably  increased,  making  what 
are  called  spring  tides.  When  they  act  at  right 
angles  to  each  other,  they  impair  each  other's  in- 
fluence and  the  tide-swell  is  decreased,  making 
what  are  called  neap  tides. 

This  constant  heaving  of  the  water  tends  to 
keep  it  pure.  It  also  agitates  to  some  extent  the 
atmosphere,  and  so  keeps  that  in  a  livelier  and 
purer  state.  It  enables  all  the  coasts  of  the  world 
to  become  vast  beds  of  a  peculiar  animal  and  ve- 
getable life,  and  twice  a  day  throws  open  the  re- 
positories to  the  plundering  hands  of  men.  The 
farmer  wants  his  sea-weed  and  salt  grass.  All 
persons,  almost,  want  their  shell-fish.  Millions 
of  people  find  their  chief  support  in  those  vast 
tribes  of  animals  that  can  only  live  where  tides 
are  felt.  Shoals  are  laid  bare  and  quickened  by 
the  sun.  The  tide-wave  brings  up  the  water 
again  with  its  flotilla  of  semi-marine  animals  and 
influences  to  impregnate  and  refresh  the  conge- 
nial sand  or  slime.  So  the  beach  swarms.  Races 
of  creatures  belonging  to  both  land  and  sea,  and 
partaking  of  the  qualities  of  both,  present  them- 
selves for  our  tables  in  countless  numbers  —  not 


MASSES  AND  DENSITIES.  81 

by  spontaneous  generation,  that  figment  of  athe- 
ists, but  by  the  good  providence  and  almighty 
power  of  God. 

How  much  matter  is  contained  in  the  earth  ? 
What  is  its  average  degree  of  compactness  ?  In 
the  year  1774  —  the  same  year  we  Americans 
were  weighing  the  maternity  of  England  in  the 
balance  and  finding  it  wanting  —  England  at- 
tempted to  weigh  the  world.  For  that  purpose, 
the  astronomer  royal,  Dr.  Maskelyne,  betook  him- 
self to  Schehallien,  in  Scotland.  He  suspended 
a  plumb-line  near  the  mountain,  and  noticed  how 
much  it  was  drawn  out  of  the  perpendicular. 
This  showed  what  proportion  the  quantity  of 
matter  in  the  mountain  bore  to  that  in  the  earth. 
Then  cuts  into  the  mountain  in  every  direction 
were  made  to  show  the  average  density  of  the 
materials  of  which  it  was  composed.  With  this, 
the  size  of  the  earth  being  known,  it  was  very 
easy  to  arrive  at  its  average  density  —  which  was 
found  to  be  about  five  and  a  half  times  that  of 
water.  This  greatly  exceeds  the  density  of  the 
surface.  So 'there  must  be  a  great  increase  of 
condensation  toward  the  center.  It  does  not  fol- 
low, however,  that  the  earth  is  perfectly  solid, 
—  the  contrary  is  known  —  only  the  parts  that  are 
solid  must  be  exceedingly  so ;  fit  walls  against 
those  tremendous  internal  fires  that  help  the  sun 
defend  us  from  the  tremendous  cold  of  space ; 
fit  walls  against  the  noxious  gases  and  vapor 


82  THIRD  LECTURE. 

which  those  fires  can  not  fail  to  generate  in  pro- 
digious amount !  For  the  earth  is  like  some  men 
—  with  a  cold  exterior,  but  a  heart  of  fire.  It  is 
a  traveling  furnace.  Wherever  we  dig  into  it, 
we  find  a  steady  increase  of  heat  —  one  degree  for 
each  fifty-four  feet  as  we  descend.  And  you  know 
how  unlike  are  the  climates  of  different  countries 
having  the  same  latitude  and  level  —  for  exam- 
ple, Southern  Europe  and  New  England  and  the 
States  due  west  of  us.  When  the  ancients  saw 
^Etna  in  eruption,  they  supposed  the  mountain  to 
be  the  chimney  to  the  great  blazing  and  resound- 
ing forges  below,  where  Vulcan  the  god-black- 
smith, with  his  journeymen-Cyclops,  were  ham- 
mering out  the  thunderbolts  of  Jupiter.  When 
we  see  JEtna  and  its  three  hundred  sister  volca- 
noes, in  all  parts  of  the  world,  in  action,  we  make 
no  question  but  that  the  immense  roaring  fires 
are  beneath  them,  if  not  the  forger  and  the 
smiths  and  the  thunderbolts.  That  the  great 
amount  of  vapor  and  gases  which  must  be  de- 
veloped by  these  fire-beds  does  not  all  escape 
through  fissures  and  volcanoes  as  fast  as  formed, 
is  plain  ;  for  the  many  violent  and  far-spreading 
earthquakes  that  occur,  come  from  the  struggles 
of  imprisoned  elements  to  escape.  They  are 
densely  accumulated  in  great  caverns.  And  it  is 
well  that  the  walls  of  these  caverns  are  denser 
than  the  densest  metals  known  to  us,  so  that 
but  comparatively  little  of  the  deadly  air  within 


MASSES  AND  DENSITIES.  83 

succeeds  in  escaping  to  the  surface.  Indeed,  so 
little  heat  escapes  that  the  earth  has  not  dimin- 
ished its  mean  temperature  by  the  three-hun- 
dredth part  of  a  degree  for  two  thousand  years. 

Can  we  also  weigh  the  moon  in  our  astronomi- 
cal balance  ?  We  can  ;  by  means  of  the  tides. 
Add  together  the  average  spring  and  neap  tides 
—  the  one  expressing  the  sum,  and  the  other  the 
difference,  of  the  solar  and  lunar  attractions.  This 
gives  us  that  part  of  the  tide-wave  which  is  due 
to  the  moon  alone.  Now  how  does  this  show  the 
quantity  of  matter  in  the  moon  ?  You  see  it  is 
a  case  of  contest  between  the  eartli  and  moon  as 
to  which  shall  have  the  water.  The  earth  pulls 
with  all  its  might  — that  is  to  say,  with  all  its  quan- 
tity of  matter ;  and  the  moon  pulls  with  all  its 
might  —  that  is,  with  all  its  quantity  of  matter. 
The  moon  acts  at  disadvantage  from  its  greater 
distance,  the  earth  acts  at  disadvantage  from 
the  tendency  to  fly  off  which  the  water  has  in  con- 
sequence of  rotation  ;  but,  when  allowance  is 
made  for  these  things,  the  position  which  the 
water  takes  between  the  two  pulling  bodies  shows 
their  relative  strength.  It  is  the  case  of  Greece 
and  Troy  dragging  at  the  body  of  Patroclus. 
The  one  tugs  at  the  head,  and  the  other  at  the 
feet  ;  the  direction  in  which  the  body  actually 
goes  shows  which  party  is  the  stronger,  and  the 
rate  at  which  it  goes  shows  how  great  the  superi- 
ority is.  At  last  the  dead  hero  moves  swiftly 


84  THIRD  LECTURE. 

toward  the  ships.  Not  eighty  wrestlLg  Troys 
could  prevent  it.  In  this  duel  for  the  seas,  we 
are  Telamonian  Ajax,  and  the  will  of  Jupiter 
besides  ;  and  it  would  require  more  than  eighty 
moons  to  turn  the  fortunes  of  the  day,  and  tear 
its  prize  from  the  stalwart  earth.  Just  as  soon 
as  we  know  the  relative  quantity  of  matter  in  the 
moon,  its  known  size  shows  what  is  its  relative 
density.  It  is  about  three-fifths  of  the  density  of 
the  earth. 

It  has  been  shown  that  the  earth  and  moon, 
making  as  they  do  a  neighborhood  by  themselves, 
must  revolve  about  their  center  of  gravity.  Now, 
since  the  earth  contains  eighty  times  as  much 
matter  as  the  moon,  this  center  must  lie  eighty 
times  nearer  to  the  center  of  the  earth  than  to 
that  of  the  moon.  But  the  eightieth  part  of  two 
hundred  and  forty  thousand  miles  is  three  thou- 
sand. So  you  see  ihat  the  point  around  which 
the  two  bodies  revolve  falls  one  thousand  miles 
within  the  earth's  surface  —  our  semi-diameter 
being  near  four  thousand.  Hence  it  is  compara- 
tively but  a  very  small  orbit  that  the  earth  de- 
scribes —  only  six  thousand  miles  across  ;  while 
the  moon  describes  one  which  is  four  hundred  and 
eighty  thousand  miles  across.  One  is  as  nothing 
to  the  other.  So,  for  popular  purposes,  it  is  com- 
mon to  consider  the  earth  as  stationary,  so  far  as 
the  moon  is  concerned,  with  the  moon  revolving 
around  it.  Turning,  then,  to  this  greater  orbit, 


ORBITS.  85 

I  will  state  some  of  the  more  interesting  facts 
about  it.  •Plainly,  it  can  not  differ  much  from  a 
circular  curve  ;  for  the  moon  always  looks  just 
about  so  large  during  its  revolution  around  us. 
If  its  distance  from  us  varies  considerably,  of 
course  its  apparent  size  ought  also  to  vary  consid- 
erably. Very  nice  measurements,  however,  of  its 
apparent  diameter  at  different  times,  show  that 
its  distance  does  alter  somewhat  —  more  than  it 
ought  on  account  of  our  being  a  little  out  of  its 
center  of  motion  ;  shows  in  fact  that  the  orbit 
must  be  what  is  called  an  ellipse  —  such  a  figure 
as  a  flexible  hoop  would  make  if  compressed  at 
opposite  sides  —  having  the  common  center  of 
gravity  about  twelve  thousand  miles  one  side  of 
its  center,  on  the  longer  axis.  It  takes  a  little 
more  than  twenty-seven  days  for  the  moon  to 
make  the  complete  circuit  of  this  orbit.  This  is 
traveling  at  the  rate  of  fifty-four  thousand  miles 
a  day.  In  passing  around  this  orbit,  our  satellite 
often  passes,  either  wholly  or  partially,  through 
the  earth's  shadow ;  giving  rise  to  lunar  eclipses. 
As  to  the  position  of  the  orbit,  we  notice  that  the 
moon  does  not  move  around  our  axis  at  right 
angles  to  it,  but  obliquely ;  so  that  the  plane  of 
the  orbit  makes  an  angle  of  about  sixty  degrees, 
with  the  axis.  This  inclination  is  of  great  ser- 
vice to  us  ;  for  it  is  owing  to  this  that  we  have  so 
much  more  lig'it  from  the  moon  in  winter  than 
in  summer ;  it  causing  the  full  moon  to  ride 


86  THIRD   LECTURE. 

highest  when  we  need  the  moct  light.  Here, 
then,  we  have  the  orbit  —  four  hundred  and 
eighty  thousand  miles  the  longest  way  across, 
lying  obliquely  across  the  axis  of  the  earth,  and 
traversed  at  a  pace  of  fifty-four  thousand  miles 
a  day.  This  is  how  the  matter  stands  now.  But 
you  are  not  to  suppose  that  it  has  always  been  so, 
or  that  it  will  always  be  so.  The  orbit  is  contin- 
ually becoming  smaller;  the  moon  with  every  revo- 
lution is  getting  nearer  and  going  faster ;  and 
some  persons  have  been  afraid  that,  at  last,  our 
neighbor  would  become  too  neighborly  —  in  fact, 
come  rushing  in  upon  us,  and  with  one  tremen- 
dous concussion  dash  every  thing  to  pieces.  The 
fact  of  the  gradual  approach  of  the  moon  to  us 
is  certain  ;  observations  establish  it  beyond  ques- 
tion. But  it  is  an  exceedingly  slow  approach, 
only  ten  seconds  on  the  time  of  revolution  being 
now  gained  in  a  century.  Still,  however  safe  we 
and  many  generations  after  us  may  be,  the  idea  of 
such  an  ending  of  an  astronomical  system  is  not 
pleasant.  We  pity  that  distant  generation  to 
come.  We  pity  the  graves  of  our  fathers  and 
our  own.  However,  we  need  not  be  alarmed. 
La  Place,  with  his  splendid  geometry,  has  shown 
from  the  doctrine  of  gravity  that  this  gradual 
contraction  of  the  orbit  is  not  to  continue  indefi- 
nitely ;  but  that,  after  millions  of  years,  it  will 
again  slowly  expand  and  finally  become  as  large 
as  ever  ;  then  contract  again  —  and  so  sweep  back- 


MUTUAL    ASPECTS.  87 

ward  and  forward  through  a  period  the  vastness 
of  which  bewilders  the  imagination.  This  change 
in  the  lunar  orbit  is  by  no  means  the  only  one. 
There  are  some  sixty  such  changes  ;  and  about 
half  that  number  are  so  considerable  that  they 
must  be  taken  account  of,  whenever  we  wish  to 
compute  the  place  of  the  moon  with  tolerable  ex- 
actness. Indeed,  the  moon's  orbit  is  a  very  wavy, 
changeable,  battered  affair.  It  is  continually  be- 
ing pushed  out  and  in,  twisted  in  this  direction 
and  in  that,  drawn  sidewise  and  edgewise,  re- 
volved in  its  own  plane  and  in  almost  every  other 
by  attractions  from  many  quarters.  Could  you 
see  the  path  which  our  satellite  actually  de- 
scribes in  space  —  could  it  leave  a  visible  wake 
as  a  rocket  does  —  you  would  wonder  greatly  at 
its  intricacy,  and  how  men  could  ever  get  able  to 
predict  the  moon's  place  on  it  to  within  five  sec- 
onds of  the  truth.  Yet  this  they  can  do.  And 
astronomers  have  found  out,  by  means  of  the  law 
of  gravity  and  that  wonderful  differential  and 
integral  calculus  which  is  the  good  Genius  of 
astronomy,  that,  notwithstanding  the  sad  usage 
which  the  lunar  orbit  gets  from  all  quarters, 
it  has,  like  much  assailed  Christian  goodness, 
within  and  around  it  all  the  elements  of  eternal 
stability. 

I  will  close  my  account  of  our  satellite  system 
by  a  few  words  as  to  the  appearance  which  its 
members  present  to  each  other. 


88  THIRD    LECTURE. 

The  appearance  of  the  moon  under  the  teles- 
cope is  very  beautiful.  And  yet  it  looks  very 
much  as  if  it  had  had  the  small-pox  in  the  natu- 
ral way,  and  had  it  sadly.  We  see  a  desperately 
pitted  and  scarred  face  —  valleys  and  mountains 
—  valleys  four  miles  deep  ;  mountains  five  miles 
high  ;  volcanoes,  conical,  ring-shaped,  with  long 
streams  of  lava  spreading  down  their  sides  in 
every  direction;  peaks  gleaming  with  the  first  kiss 
of  the  morning  sun  ;  shadows  advancing  across 
the  plains.  As  to  atmosphere  and  water  on  the 
moon,  appearances  are  indecisive.  Some  things 
seem  to  prove  their  presence,  and  other  things 
seem  as  strongly  to  prove  their  absence.  Cer- 
tainly the  moon  has  never  any  clouds.  However, 
if  it  could  be  demonstrated  that  it  has  neither  air 
nor  water,  it  would  not  follow  that  it  has  no  in- 
habitants. It  would  only  follow  that,  if  there  are 
living  beings  there,  they  must  be  differently  con- 
stituted from  ourselves.  And  who  will  undertake 
to  show  that  beings  widely  diverse  from  us  are 
impossible  or  improbable  in  the  universe  of  so 
versatile  and  magnificent  a  Creator  as  He  who 
spake  into  being  these  wonderful  worlds  of  as- 
tronomy ? 

This  is  how  the  moon  looks  from  the  earth. 
A.nd  how  does  the  earth  look  from  the  moon,  if 
there  are  people  there  to  see  ?  Half  of  the  moon 
never  sees  us  at  all.  To  the  other  half  we  seeni 
a  brilliant  or1)  about  thirteen  times  larger  than  the 


MUTUAL    ASPECTS.  89 

moon  seems  to  us — always  occupying  nearly  the 
same  place  in  the  sky  —  successively  crescent,  gib- 
bous, and  full  —  in  fact,  another  moon.  Under  a 
telescope,  what  with  our  clouds  and  seas  and  val- 
leys and  mountains,  the  earth  would  present  even 
a  more  pocked  aspect  than  the  moon  does  to  us. 
Never  did  veteran  come  home  from  the  war  with 
half  so  scarred  and  battered  a  countenance !  But 
never  mind,  ancient  earth !  Thou  hast  a  better 
look  on  closer  acquaintance.  And,  besides, "  hand- 
some is  that  handsome  does,"  and  thou  gener- 
ously givest  us  flowers  and  fruits  and  harvests 
and  coal  and  silver  and  gold  and  gems  ;  green 
fields,  stately  forests,  musical  streams ;  sweet 
vales  of  Tempe,  hoary  Alps  sublime,  august 
oceans  with  their  eternal  anthems  ;  above  all,  a 
standing  place  on  which  Holy  Christ  and  sinful 
we  may  work  out  for  ourselves  the  wonders  of 
eternal  life. 


IV. 

PLANET    SYSTEMS. 


91 


IV.   PLANET  SYSTEMS. 

EXAMPLE  —  SOLAR  SYSTEM. 

1.  ORDER  OF  BODIES 93 

2.  PERIODS  . 103 

3.  DISTANCES  FROM   SUN 105 

4.  SHAPES  AND   INCLINATIONS  OF  ORBITS    .        .        .  in 

5.  SIZES 115 

6.  VELOCITIES 117 

7.  MASSES  AND  DENSITIES nS 

8     PERTURBATIONS                                                                         .  120 


92 


FOURTH    LECTURE, 


PLANET   SYSTEMS. 

IN  my  last  lecture  I  gave  an  example  of  the 
First  Order  of  Systems  among  the  heavenly 
bodies  —  the  Satellite  Systems.     This  evening  I 
propose  to  give  an  example  of  the  Second  Order 
—  the  Planet  Systems,  or  systems  eacli  of  which 
is  composed  wholly  or  in  part  of  Satellite  Systems 
revolving  about  a  self-luminous  body  or  sun. 

The  rotation  of  the  earth  makes  all  the  heav- 
enly bodies  seem  to  move  across  the  sky  in  parallel 
lines,  without  any  disturbance  of  their  mutual  po- 
sitions. But  some  of  these  bodies  have  very  much 
motion  of  another  kind  —  a  motion  among  them- 
selves. They  go  this  way,  and  they  go  that ;  they 
go  forward,  and  they  go  backward  —  describing 
quite  rapidly  very  irregular  paths  on  the  sky.  I 
have  already  called  your  attention  to  these  very 
roving  bodies,  under  the  names  of  planets  and  com- 
ets. About  ninety  planets,  and  some  one  hundred 
and  eighty  comets,  have  been  carefully  noticed. 


94  FOURTH  LECTURE. 

Some  of  these  change  their  places  among  the  other 
stars,  on  the  average,  as  much  as  eight  times  the  ap- 
parent diameter  of  the  sun  in  a  single  day  —  indeed 
some  comets  have  been  known  to  traverse,  in  the 
same  time,  eighty  times  this  diameter.  Besides 
these,  the  sun  itself  is  found  to  be  a  great  traveler, 
though  never  a  retrograde  one  —  making  the 
whole  circuit  of  the  heavens  in  a  year.  Now,  the 
thing  to  be  particularly  noted,  is  the  great  differ- 
ence in  amount  between  the  apparent  motions  of 
these  bodies  and  the  apparent  motions  of  all  others. 
Why,  all  others  have  no  motions  at  all,  that  ordi- 
nary observers  can  detect,  and  hence  are  called 
fixed  stars.  And  when  astronomers  mount  their 
instruments,  and  do  succeed  in  detecting  small  an- 
nual changes  of  place  among  them,  they  find  that 
the  greatest  of  these  changes  is  a  thousand  times 
less  than  that  of  the  slowest  planet.  Now  what 
makes  this  great  chasm  ?  Why  do  these  three  hun- 
dred bodies  seem  to  move  so  much,  while  all  the 
rest  seem  to  move  so  little  ?  There  is  but  one  an- 
swer. Those  greatly  moving  bodies  are  greatly 
nearer  to  us  than  are  the  others.  There  is  a  great 
interval  between  the  two  classes  of  bodies  in  space, 
corresponding  to  the  interval  between  them  in  mo- 
tion. If  there  were  no  space-chasm  between  them, 
the  law  of  gravity  would  require  them  all  to  belong 
to  the  same  system  of  revolution ;  of  course,  the 
real  motions,  and  so  the  apparent,  of  all  would  be 
of  the  same  general  order  of  magnitude.  Suppose 


ORDER  OF  BODIES.  95 

yourselves  at  sea  in  a  fleet.  Here  are  three  hundred 
ships  within  two  miles  of  you.  Some  are  standing 
this  way  and  some  that,  some  advancing  and  some 
retrograding ;  but  all  noticeably  changing  their 
positions  with  respect  to  you  and  each  other  every 
minute.  Now  let  another  fleet  appear  on  the  hori- 
zon. You  count  a  thousand  tiny  masts.  Their 
progress  seems  as  petty  as  their  size,  hours  scarcely 
showing  any  change  of  position.  What  say  you?" 
That  those  Liliput  ships  with  their  Liliput  mo- 
tions arc  mingled  with  your  own  squadron,  be- 
cause, forsooth,  you  happen  to  see  them  between 
the  neighboring  hulls  and  masts  ?  Not  so.  If 
they  belonged  to  you,  they  would  take  signals 
from  your  flag-ship,  and  all  the  exuberant  ship- 
ping in  sight  would  have  a  family  likeness  as  to 
the  character  and  degree  of  their  sailing.  But  here 
is  quite  another' order  of  motions.  They  plainly 
belong  to  another  fleet,  under  another  admiral, 
far  away  in  the  offing ;  and  distance  has  dwarfed 
both  figure  and  motion.  A  great  breadth  of  sea 
lies  between  the  two  navies.  We  reason  in  the 
same  way  in  regard  to  the  heavenly  bodies. 
These  three  hundred  bodies,  more  or  less,  that 
show  so  much  motion,  we  conclude  to  belong  to 
our  fleet  of  stars  ;  the  others  that  scarcely  stir  on 
the  sight  belong  to  other  fleets  or  fleet,  separated 
from  ours  by  a  wjde  interval.  The  three  hundred 
and  the  earth  are  astronomical  neighbors.  The 
three  hundred  and  the  earth  are  a  system  by 


96  FOURTH  LECTURE. 

themselves  —  if  you  please,  an  astronomical  Leon- 
idas  and  his  Spartans,  keeping  ward  at  the  Ther- 
mopyla3  of  the  sky,  and  endeavoring  to  beat  off 
the  crowd  of  Chaldean  astronomers  that  seek  to 
reach  the  very  heart  of  the  heavens.  They  can 
not  be  beaten  off  By  dint  of  numbers  and  pa- 
tience, if  not  of  boldness  and  genius,  they  shall 
break  through.  The  very  heart  of  that  Greece 
shall  be  laid  open. 

According  to  the  law  of  gravity,  all  the  mem- 
bers of  this  system  must  be  in  a  course  of  revo- 
lution about  their  common  center  of  gravity. 
Where  is  this  common  center  ?  It  may  be  an  in- 
visible point  out  in  the  void  of  space,  far  away 
from  any  member  of  the  system  ;  and  again,  as  in 
the  case  of  the  earth  and  moon,  it  may  lie  near 
the  center  of  some  body.  The  ancients  always 
assumed  the  last  supposition  to  be  the  true  one ; 
and  further  assumed  that  the  earth  is  that  central 
body  about  which,  not  only  the  sun  and  planets 
and  comets,  but  all  the  huge  varieties  of  nature 
revolve.  Themselves  were  the  center  of  creation. 
It  is  something  in  their  favor  that  they  did  not 
know  how  large  creation  was.  But  the  children 
are  wiser  than  the  sires.  Since  the  time  of  Co- 
pernicus— that  astronomical  Columbus — men  have 
seen  reason  to  change  their  opinions  on  a  great 
many  subjects  ;  on  this  among  •  the  rest.  Now 
we  know  that  the  sun  occupies  nearly  the  center 
of  motion  of  that  system  of  planets  and  comets 


ORDER   OF  BODIES.  97 

to  which  we  belong.  This  should  have  been  sus- 
pected from  the  beginning  —  especially  in  view  of 
the  desirableness  of  having  the  only  self-lurninous 
body  in  the  system  placed  somewhere  near  its 
center.  And  the  suspicion  should  have  been 
easily  turned  into  a  conviction.  Suppose  the 
earth  to  be  practically  at  the  center  of  motion. 
Then  all  the  planets  and  comets  would  seem  to 
describe,  in  a  course  of  perpetual  progress,  regular 
circles  about  us;  whereas  they  all,  without  ex- 
ception, advance  and  retreat  on  most  irregular 
curves.  So  the  earth  can  not  be  the  center. 
Next,  suppose  one  of  the  other  members  of  the 
system  to  be  it.  Then  that  central  body,  being 
the  center  of  our  motion,  would  appear  to  describe 
in  unbroken  progress  a  regular  circle  among  the 
fixed  stars.  Now  the  sun  is  the  only  body  in  the 
system  which  fulfills  this  condition.  Its  apparent 
path  is  a  regular  circle ;  described  in  one  year, 
without  any  retrogradations  whatever ;  while,  as 
I  have  said,  every  other  member  of  the  system 
apparently  moves  on  a  very  irregular  line  —  now 
forward,  now  backward,  now  sidewise,  now  stop- 
ping altogether  —  in  short  the  picture  of  irresolu- 
tion. More  eccentric  vagrants  than  those  planets 
and  comets  seem  to  be,  it  would  be  hard  to  find. 
But  the  sun  marches  steadily  along.  He  seems 
to  know  what  lie  wants  and  the  way  to  it.  Right 
forward  on  the  periphery  of  a  great  circle,  with- 
out a  step  to  the  right  hand  or  to  the  left,  he 


98  FOURTH  LECTURE. 

presses,  till  he  comes  around  to  the  same  fixed 
star  again.  So  the  sun  is  practically  the  center 
of  the  system.  It  is  the  sun,  and  not  the  earth, 
who  is  the  patriarch  of  yonder  seemingly  wayward 
and  disorderly  family,  and  who  —  shall  we  say  it 
—  is  responsible  for  this  misbehavior.  But  things 
are  not  what  they  seem.  There  is  nothing  dis- 
orderly in  the  universe  save  intelligent  beings. 
Could  we  stand  at  the  sun,  the  motion-center  of 
all  these  graceless  nomads  of  the  sky,  they  would 
no  longer  seem  so  indictable  for  vagrancy  and  in- 
subordination. All  their  zigzags  would  be  straight- 
ened out,  all  their  stops  and  retreats  would  be 
turned  into  one  constant  advance.  See  how  much 
depends  on  having  the  right  stand-point  for  view- 
ing things  !  And  the  wisdom  of  the  Great  Architect 
of  astronomical  systems  is  saved  from  aspersion 
as  we  see  the  chief  source  of  light  and  heat  in  our 
stellar  community  so  placed  as  to  be  of  the  great- 
est service  to  the  greatest  number  —  so  placed  as 
to  oppose,  as  much  as  possible,  extreme  variations 
of  illumination  and  temperature  on  any  world. 

But  now  what  are  these  bodies  thus  revolving 
about  the  sun  ?  First,  we  have  the  earth  and 
moon  —  one  satellite  system.  Next,  take  a  tele- 
scope —  a  common  spy-glass  will  answer  —  and 
bring  it  to  bear  on  the  planet  Jupiter.  You  see 
a  well-defined  disc,  and  four  bright  points  in  its 
immediate  neighborhood.  Watch,  and  you  shall 
notice  these  bright  points  approaching  the  planet, 


ORDER   OF  BODIES.  99 

crossing  its  face,  going  a  little  beyond  it,  then 
coming  back  to  it,  disappearing  behind  it,  after  a 
while  appearing  on  the  opposite  side,  and  then  re- 
ceding from  it -as  far  as  before  ;  watch  them,  and 
you  shall  find  them  keeping  with  the  planet  in  all 
its  wanderings  among  the  stars,  advancing  when 
it  advances,  retreating  as  it  retreats,  becoming 
stationary  relatively  to  other  stars  when  it  becomes 
stationary.     Plainly,  another  satellite  system  — 
a  reflecting  primary,  with  four  moons  waiting  upon 
and   revolving  around  it.     There   is  the  planet 
Saturn !     Look  at  it  with  a  more  powerful  glass, 
and  see  —  what  you  shall  see.     If  your  eyes  are 
good  and  your  telescope  is  of  the  first  class,  you 
will  by  pa'tient  watching  be  able  to  detect  eight 
bright  atoms  in  the  neighborhood  of  a  curiously 
beringed   disc,   behaving   toward   it  just   as   the 
satellites  of  Jupiter   do   toward   their   primary. 
Plainly  Janissaries  ;  plainly,  another  satellite  sys- 
tem —  a  reflecting  primary,  with  eight  moons  re- 
volving around  it.  —  Hunt  up  the  planet  Uranus, 
never  visible   to  the  naked  eye,  but  seen  well 
enough  with  an  instrument ;.  and,  if  you  manage 
your  instrument  as  well  as  Sir  W.  Herschel  and 
his  sister  did  theirs,  eighty-four  years  ago,  you  will 
see  that  reflecting  disc  moving  about  with  what  is 
evidently  its  body-guard  of  six  moons.     Another 
satellite  system  !  —  So  of  Neptune  —  a  newly-dis- 
covered planet.     Hunt  patiently  in  its  close  neigh- 
borhood, as  it  shines  in  the  field  of  a  powerful 


100  FOURTH  LECTURE. 

telescope,  and,  if  you  do  as  well  as  Struve  did  at 
Pulkova,  and  Bond  at  Cambridge,  you  will  find  at 
least  one  minute  point  of  light  playing  the  hench- 
man to  his  chief.  Another  satellite  system ! 
Thus  it  appears  that  we  have  a  great  system  of 
heavenly  bodies,  composed  largely  at  least  of 
satellite  systems  revolving  about  the  sun.  No 
satellites  have  as  yet  been  discovered  in  connection 
with  other  planets.  This  discovery,  however,  may 
yet  be  made.  One  has  been  suspected  waiting 
on  beautiful  Venus.  In  short,  we  have  an  ex- 
ample of  a  stellar  system  of  the  second  order. 
We  have  a  Planet  System.  We  have  a  number 
of  heavenly  sires  with  their  comely  families  of 
various  sizes  about  them,  still  bound  in  invisible 
bonds  to,  and  in  course  of  circulation  around,  the 
ancient  and  majestic  grandsire  —  whose  eye,  how- 
ever, is  not  yet  dim,  nor  natural  force  abated. 

Having  thus  found  our  Planet  System,  let  us 
proceed  to  consider  its  chief  points  of  interest. 
And,  first,  the  order  of  the  bodies  composing  it. 
Suppose  one  to  start  from  the  sun  and  travel  to  the 
frontiers.  What  body  would  he  reach  first,  what 
secondly,  and  so  on  ;  supposing  them  all  ranged 
on  the  same  side  of  the  sun,  at  their  average  dis- 
tances ?  At  first  glance  it  looks  a  hard  matter  to 
answer  these  questions.  The  members  of  the 
system  seem  quite  too  insubordinate  to  adhere  to 
any  order  of  position  and  revolution  that  may 
have  been  assigned  to  them.  Here,  is  one  refrac- 


ORDER   OF  BODIES.  101 

tory  planet  with  its  strange  path  ;  there,  a  still 
more  refractory  comet  with  its  stranger  ;  one  is 
going  this  way,  another  that ;  one  is  creeping 
northward,  another  striding  westward  —  in  short, 
it  is  a  perfect  maze  of  positions,  directions,  and 
motions  that  we  see.  But  there  is  a  clew  to  the 
labyrinth.  There  is  a  key  to  this  sky-cipher  and 
hieroglyphic.  And  it  is  something  that  does  not 
look  particularly  like  a  key  at  first  sight,  though 
it  can  he  made,  in  connection  with  the  law  of 
gravity,  to  interpret,  not  only  the  order,  but  also 
the  periods  and  distances  from  the  sun  of  all  the 
members  of  our  system.  This  Rosetta  stone  is 
the  average  apparent  daily  motions,  which  any  one, 
almost  without  instrument  but  with  a  plenty  of  pa- 
tience, could  approximately  determine  for  him- 
self; and  which,  with  such  instruments  as  every 
observatory  is  now  furnished  with,  can  be  deter- 
mined with  admirable  exactness.  A  word  as  to 
the  general  method.  The  law  of  gravity  proves 
that  the  more  remote  a  revolving  body  is  from 
its  center  of  revolution,  the  more  slowly  it  must 
move ;  and,  of  course,  the  more  slowly  it  must 
seem  to  move,  as  seen  from  that  center.  Hence, 
if  we  can  only  find  how  the  motions  of  the  planets  * 
and  comets,  as  seen  from  the  sun,  compare  with 
each  other,  we  shall  know  their  relative  distances 
from  that  body.  Now  this  is  easily  done.  We 
have  merely  to  find  what  their  average  motions 
are  as  seen  from  the  earth.  As  we  are  nearer 


102  FOURTH  LECTURE. 

to  each  by  a  whole  diameter  of  the  earth's  orbit 
at  one  time  than  at  another,  taking  the  average 
reduces  the  motion  to  what  it  would  appear  mid- 
way between  opposite  sides  of  the  orbit.  Well, 
being  thus  reduced,  how  do  the  motions  compare 
with  each  other  ?  For  the  planets,  they  decrease 
in  the  following  order :  Mercury,  Venus,  Earth, 
Mars,  some  eighty  small  bodies  called  asteroids 
or  planetoids  as  you  may  prefer,  Jupiter,  Saturn, 
Uranus,  Neptune.  This  then  is  the  order  in  which 
these  several  planets  would  be  reached  by  one 
going  outward  from  the  sun,  could  they  all  be  ar- 
ranged on  the  same  side  of  that  luminary  at  their 
average  distances.  Comets  would  be  encountered 
in  great  numbers  all  along  the  glittering  journey 
—  the  best  known  of  them  in  the  following  order ; 
Encke's,  Biela's,  Halley's,  comet  of  1811,  comet 
of  1680. 

Such  are  the  various  places  which  his  glittering 
nobles  hold  in  that  great  court  which  the  solar 
monarch  maintains  in  the  sky.  Mercury  holds 
the  place  of  honor  ;  he  waits  perpetually  in  pres- 
ence. Neptune  is  a  mere  hanger-on  at  court  — 
getting  comparatively  few  rays  of  favor,  and 
obliged  to  content  himself  with  exceedingly  dis- 
tant and  dim  views  of  his  sovereign.  The  earth 
has  a  golden  mean  of  position  —  not  a  Steenie,  in 
the  dangerous  post  of  a  favorite  putting  up  at  the 
palace  —  not  a  governor-general  of  Van  Dieman's 
Land  and  all  British  Antipodes  —  but  Duke 


PERIODS  OF  PLANETS.  103 

Percy,  living  in  an  independent  way  on  his  estates 
in  Northumberland,  in  a  very  genial  temperature 
of  court  favor,  neither  loved  too  much  nor  too 
little,  always  welcome  and  never  wanted,  far 
enough  from  St.  James's  and  not  too  far. 

How  long  are  the  members  of  our  system  in 
traveling  around  the  sun?  The  average  daily 
motion,  as  seen  from  the  sun,  answers  this  ques- 
tion also.  For  if  you  find  this  motion  to  be  —  say 
IQ — yOU  know  that  it  will  take  three  hundred  and 
sixty  days  for  the  planet  to  accomplish  the  whole 
circumference  of  the  heavens.  If  Mercury  moves 
around  the  sun  at  a  mean  daily  rate  of  4°  5',  as 
it  does,  it  will  take  it  eighty-eight  days  to  go  360°, 
or  an  entire  circuit.  And  so  on.  In  this  way  we 
find  the  period  of  Mercury  to  be  three  months, 
of  Venus  seven  months,  of  the  Earth  one 
year,  of  Mars  two  years,  of  Jupiter  twelve,  of 
Saturn  twenty-nine,  of  Uranus  eighty-four,  of 
Neptune  one  hundred  and  sixty-four.  Ask  that 
man  of  silver  hairs  how  old  he  is.  Eighty-four 
years,  does  he  say  ?  Then  he  was  born  when 
Ursrnus  was  last  at  its  present  point  in  its  orbit 
—  the  point  where  Sir  William  Herschel  was 
then  finding  it.  The  child,  whose  fresh,  dewy  orbs 
to-day  look  up  wonderingly  at  the  spangled  vault 
where  Neptune  hides  itself,  will  have  grown  up, 
fought  life's  battle,  grown  old,  died,  and  lain  in 
his  grave  a  hundred  years,  by  the  time  that  fron- 
tier planet  is  able  to  get  around  again  to  its  pres- 


104  FOURTH   LECTURE. 

ent  place  in  the  sky  !  According  to  the  Neptunian 
calendar,  it  is  only  thirty-six  years  since  the  cre- 
ation of  Adam  !  But  even  such  years  are  trifling 
when  compared  with  those  of  some  comets.  What 
think  you  of  a  voyage  about  the  sun  requiring 
four  thousand  of  our  years  for  its  completion  ? 
The  comet  of  1811,  when  it  last  saw  the  earth, 
saw  it  yet  dripping  with  the  waters  of  the  flood  ; 
the  comet  of  1680,  when  it  last  saw  the  earth, 
saw  it  without  form  and  void,  and  prophesying 
but  faintly  of  an  Eden  and  an  Adam  still  three 
thousand  years  distant.  When  it  sees  the  earth 
again,  where  shall  we  be  —  ourselves,  our  homes, 
our  cities,  our  race  ?  May  Heaven  grant  that  the 
next  nine  thousand  years  shall  suffice  to  prepare  for 
exhibition  to  the  gaze  of  that  mighty  voyager,  the 
predicted  new  heavens  and  new  earth  in  which 
shall  dwell  righteousness ! 

Having  the  periods  of  the  members  of  our  sys- 
tem, and  the  actual  distance  of  one  of  them  from 
the  sun,  we  can  find  the  distances  of  all  the  rest. 
For  the  mathematics  of  Newton  have  proved,  that, 
in  case  the  central  body  of  a  system  is  greatly 
superior  in  mass  to  the  sum  of  all  the  others,  it 
follows  from  the  law  of  gravity  that  the  squares 
of  the  periods  of  any  two  of  them  are  as  the 
cubes  of  their  mean  distances  from  the  center. 
That  this  condition  is  fulfilled  in  the  case  of  our 
own  system  is  clear  ;  for  all  observation  shows 
that  the  sun,  relatively  to  the  planets  and  comets, 


DISTANCES  FROM  THE  'SUN.  105 

is  substantially  at  rest.  Hence  the  law  which 
Newton  proved  is  applicable  to  our  system  —  the 
squares  of  the  periodic  times  are  as  the  cubes  of 
the  mean  distances  from  the  sun.  By  the  help  of 
this  law  and  the  periods,  if  we  can  find  the  mean 
distance  of  one  planet  from  the  sun,  we  can  find 
the  mean  distances  of  all  the  planets.  Let  us  then 
find  the  distance  of  the  earth  from  the  sun,  as  a 
means  to  that  of  every  other  member  of  the 
system  whose  period  is  known. 

One  very  easy  way  of  approximating  to  our 
distance  from  the  sun  was  employed  by  the  an- 
cients. Sometimes  a  half-moon  is  visible  during 
the  day.  A.t  such  a  time  let  a  line  be  drawn  from 
the  center  of  the  sun  to  that  of  the  moon,  thence 
another  line  to  the  center  of  the  earth,  thence 
another  back  to  the  center  of  the  sun  —  making 
a  right-angled  triangle.  Now  let  us  measure  the 
angular  distance  of  the  moon  from  the  sun. 
This,  with  the  known  distance  of  the  moon  from 
the  earth,  enables  us  to  find  with  the  greatest  ease 
that  other  side  of  the  triangle  which  is  the  dis- 
tance between  the  centers  of  the  sun  and  earth. 
But  this  is  only  a  rough  approximation.  In  these 
times  astronomers  would  curl  the  lip  at  such 
coarse  measurements  as  these.  Why,  then,  not 
find  our  distance  from  the  sun  in  the  same  way 
we  did  our  distance  from  the  moon  —  that  is,  by 
noticing  how  much  the  sun  is  apparently  dis- 
placed on  the  sky  by  a  given  change  in  our  place 


106  SOURTH  LECTURE. 

on  the  earth  —  that  is  to  say,  by  its  parallax  ? 
This  will  do :  only,  on  account  of  the  exceeding 
smallness  of  the  solar  parallax,  we  can  not  employ 
the  same  method  for  determining  it  as  was  used 
in  the  case  of  the  moon.  A  very  accurate  method, 
however,  was  discovered  by  Dr.  Halley,  the 
friend  of  Newton,  and  bequeathed  by  him  to  the 
next  generation  of  astronomers,  to  be  used  when 
fitting  occasion  should  arrive.  This  was  the 
method.  Occasionally  the  planet  Yenus  crosses 
.the  sun's  disc.  Now,  if  we  can  only  find  how 
much  Venus  is  displaced  on  the  disc  at  that 
time  by  our  going  a  given  distance  on  the  earth, 
we  can  know  how  much  the  sun  is  displaced  on 
the  sky  by  the  same  change  of  place  ;  for  the  one 
displacement  is  to  the  other  as  the  distance  of 
Venus  from  the  sun  is  to  her  distance  from  the 
earth.  But  this  latter  ratio  is  easily  obtained 
from  the  average  apparent  daily  motions  of  the 
two  bodies,  by  means  of  that  law  connecting  the 
periods  and  distances  which  has  just  been  referred 
to.  It  is  as  2-J-  to  1.  So,  in  1769,  the  English, 
French,  Russian,  and  other  European  Governments 
fitted  out  expeditions  to  observe,  from  as  widely 
separated  parts  of  the  world  as  possible,  the  transit 
of  Venus  which  occurred  that  year.  One  corps  of 
observers  went  to  Wardhus  —  a  small  island  on  the 
Coast  of  Lapland ;  another  corps  was  carried  by  the 
celebrated  Captain  Cook  to  Otaheite,  now  Tahiti, 
in  the  South  Sea.  All  possible  means  were  used 


DISTANCES  FROM  THE  SUIT.  107 

to  secure  extreme  accuracy  of  result.  It  was  un- 
derstood by  all  parties,  that  they  were  measuring 
a  base  line  that  would  be  used  in  determining  all 
the  other  distances  in  our  planetary  system,  and 
perhaps  distances  stretching  across  the  void  of 
space  to  where  other  isles  of  light,  and  archipela- 
goes of  such  isles,  go  swimming  about  other  glow- 
ing continents  in  endless  circumnavigations.  So 
the  science  and  art  of  the  day  did  their  very  best. 
The  extremest  refinements,  both  of  observation 
and  theory,  were  brought  to  bear.  Spider  lines 
were  split  by  the  observer,  and  differentials  by  the 
mathematicians.  The  result  was  8"  57  —  about 
^JQ-  of  the  sun's  apparent  diameter,  —  for  the  mean 
change  made  in  the  sun's  place  by  our  passing 
from  the  surface  to  the  center  of  the  earth.  From 
this,  by  simplest  triangle-proportion,  was  found  our 
mean  distance  from  the  sun  —  95,298,260  miles. 
Taking  this  distance  and  the  law  expressing 
the  relation  between  the  distances  and  the  periods, 
we  come,  by  a  simple  proportion,  to  a  knowledge 
of  the  average  distances  of  all  the  principal  bodies 
in  our  system.  We  find  Mercury  to  be  thirty- 
seven  millions  of  miles  from  the  sun,  Venus 
sixty-eight  millions,  Mars  one  hundred  and  forty- 
five  millions,  Jupiter  four  hundred  and  ninety- 
five  millions,  Saturn  nine  hundred  millions, 
Uranus  eighteen  hundred  millions,  Neptune  two 
thousand  eight  hundred  millions.  Some  of  the 
comets  have  still  greater  mean  distances.  That 


108  FOURTH  LECTURE. 

of  the  cornet  of  1811  is  not  far  from  twenty-two 
hundred  millions  of  miles ;  while  that  of  the 
comet  of  1680  astonishes  us  with  the  mighty 
stretch  of  forty-four  thousand  millions  —  sixteen 
times  the  solar  distance  of  Neptune  ! 

You  see  that  we  have  come  to  a  new  order  of 
distances  in  our  astronomy.  The  distances  we 
have  to  deal  with  in  our  every-day  life  are  such 
as  we  pass  over  in  going  to  our  fields,  neighbors, 
schools,  churches,  markets,  occasionally  a  neigh- 
boring city  ;  and  hours  and  miles  answer  very 
well  to  express  such  movements.  Next,  we  learn 
that  the  earth  we  live  on  is  nearly  eight  thousand 
miles  through  —  this  lifts  us  to  quite  another 
plane  of  distances.  Our  common  walks  and  rides 
are  lost  by  the  side  of  such  mammoth  lines. 
Then  we  learn  that  the  moon  is  two  hundred  and 
forty  thousand  miles  away.  See  another  plane 
and  order  of  distances  still !  The  word  "  miles  " 
begins  to  empty  itself  of  its  meaning  in  such  com- 
binations. But  we  go  on  to  learn  that  the  moon 
is  at  our  very  door  as  compared  with  other  mem 
bers  of  our  planet  system  —  that  the  sun  is  four 
hundred  times  as  remote ;  Neptune  eleven  thou- 
sand times  ;  while  the  comet  of  1680,  that  Minis 
ter  of  Foreign  Affairs  to  his  Solar  Majesty,  buries 
itself  in  that  tremendous  Ultima  Thule  whose  dis 
tance  is  one  hundred  and  eighty  thousand  times 
that  of  the  moon.  Do  you  take  the  meaning  of 
such  enormous  intervals  ?  Have  miles  any  mean- 


DISTANCES  FROM  THE  SUN.  109 

ing  left  to  them  ?  Does  not  the  bight  of  this 
last  plane  of  our  astronomical  arithmetic  seem 
almost  too  dizzy  and  cloud-mixed  to  stand  upon  ? 
And,  when  you  are  told  that  a  car,  running  ex- 
press from  the  sun  to  that  frontier  of  this  planetary 
system  of  ours,  would  not  need  to  put  on  brakes 
for  five  hundred  thousand  years,  do  your  concep- 
tions seem  any  the  less  dizzy  and  astounded  ?  In 
that  great  calculus  which  has  done  so  much  for 
astronomy  we  encounter  infinitely  small  quanti- 
ties of  different  orders.  The  zeros  of  the  first 
order  are  of  no  account  as  compared  with  finite 
quantities  —  zeros  of  the  second  order  of  no  ac- 
count as  compared  with  those  of  the  first  —  zeros 
of  the  third  of  no  account  as  compared  with  the 
second  —  and  so  on.  In  practical  astronomy  we 
have  the  other  end  of  the  scale  —  infinites  instead 
of  infinitesimals  —  successive  orders  of  largeness 
and  grandeur  gradually  ascending  into  the  dizziest 
bights  of  sublimity,  to  each  of  which  that  below 
it  is  as  nothing. 

On  comparing  among  themselves  the  various 
distances  of  the  members  of  our  planetary  system 
from  the  sun,  certain  interesting  facts  become  ap- 
parent. At  our  distance  that  luminary  appears  — 
you  know  how  large  —  and  so  bright  that  you  can 
not  look  at  it  a  single  moment  with  unwounded 
eyes.  The  brightest  flame  disappears  when  held 
up  between  it  and  us.  At  our  equator  men  get 
from  its  disc  an  average  temperature  of  70°  or 


110  FOURTH  LECTURE. 

80°  Fahrenheit.  Now,  suppose  our  thoughts  to 
be  chariots,  and  let  us  travel  off  in  them  toward 
the  sun.  At  the  distance  of  Mercury,  the  sun 
would  appear  six  times  larger  and  brighter  than 
it  did  on  the  earth,  and  must  be  that  number  of 
times  hotter  —  other  things  being  equal.  What 
a  summer-two  o'clock  in  the  afternoon  the  Mer- 
curians  must  have !  If  the  supposed  planet 
Vulcan  were  real,  the  sun  from  it  would  appear 
fifty  times  as  large  and  bright  as  it  does  at  the 
earth  ;  and  the  mean  heat  at  the  most  exposed 
parts  of  the  planet  would  be  more  than  3000°. 
What  a  long  thermometer,  not  to  say  incombus- 
tible, must  the  Vulcanians  require !  Going  on 
still,  as  we  near  the  surface  of  the  sun,  it  expands 
so  as  to  fill  a  half-heaven  with  its  disc,  and  the 
heat  is  now  three  hundred  thousand  times  what 
we  have  been  accustomed  to  on  the  earth.  Had 
we  not  had  the  prudence  to  provide  ourselves  with 
a  jerkin  of  the  very  best  asbestos,  were  not  our 
thought-chariot  itself  a  salamander  safe  of  the 
very  best  quality,  our  traveling  would  now  be 
for  ever  ended.  But,  as  it  is,  we  are  able  to  pass 
around  the  sun ;  and  then,  speeding  outward  as 
only  thought-chariots,  fancy-driven,  can  —  past 
belted  Jupiter,  past  Saturn  with  its  three  won- 
drous rings  —  we  stop  not  till  we  reach  Neptune. 
Looking  back,  we  see  the  sun  dwindled  to  the  size 
of  Venus  —  nine  hundred  times  less  than  we  saw 
it  from  the  earth,  and  nine  hundred  times  as  dim 


DISTANCES  FROM  THE  SUN.  Ill 

and  cold ;  and  yet  giving  as  much  light  as  six 
hundred  of  our  moons.  And,  if  our  courage 
does  not  fail  us  on  these  dim  frontiers  and  with 
the  thermometer  already  standing  some  50,000° 
below  zero  —  if  it  is  not  too  much  of  a  transition 
even  for  us,  thought-pavilioned  as  we  are,  to  pass, 
all  in  a  single  minute,  from  the  immeasurable 
furnace  of  the  sun  to  the  immeasurable  refriger- 
ator of  the  very  pole  of  our  planetary  system  — 
let  us  keep  on  one  stage  further  to  where  the  sun 
appears  a  star  of  inappreciable  diameter,  and 
where,  in  the  heart  of  eternal  night  and  of  infinite 
congelation  multiplied  by  two  hundred  and  fifty- 
six,  cruises  the  last  known  picket  of  our  planetary 
system,  the  comet  of  1680.  We  can  not  deny 
that,  if  worlds  thus  situated  are  peopled,  it  must 
be  with  beings  very  differently  constituted  from 
ourselves.  And  what  of  that  ?  We  will  not  be 
guilty  of  the  unphilosophy  of  assuming  that  the 
Infinite  Creator  has  made  but  one  pattern  of  liv- 
ing creatures,  or  that  the  patterns  are  not  as 
various  as  the  circumstances  of  the  spheres  which 
his  almighty  hand  has  shaped  and  sent  whirling 
through  the  void. 

You  notice  that  I  have  spoken  of  average  dis- 
tances from  the  sun.  I  did  this,  because  I  did 
not  wish  to  assume  what  is  contrary  to  fact ;  viz., 
that  the  orbits  of  the  planets  and  comets  are  cir- 
cular. Instead  of  being  circles,  they  are  all  ellip- 
ses. This  does  not  follow  from  the  law  of  gravity, 


112  FOURTH  LECTURE. 

as  some  treatises  on  astronomy  seem  to  intimate. 
No  body  revolves  about  another  through  force  of 
gravity  alone.  Mere  gravity  would  cause  them 
to  rush  together  on  the  same  straight  line.  It 
takes  both  gravity  and  a  projectile  force  across  the 
direction  of  gravity  to  make  a  system  of  revolv- 
ing bodies.  The  nature  of  the  curve  described  — 
whether  a  circle  or  one  of  those  other  sections  of 
a  cone  which  mathematicians  call  ellipses,  parab- 
olas, and  hyperbolas  —  depends  on  the  relation 
which  the  attracting  force  bears  in  amount  and 
direction  to  the  projectile.  Now,  as  we  do  not 
know  what  the  force  and  direction  were  with 
which  Deity  launched  the  various  members  of  our 
system  into  space,  we  are  forced  to  rely  on  obser- 
vation to  settle  the  nature  of  the  curves  they 
describe.  Let  us  then  observe.  If  the  orbits 
were  exact  circles,  the  law  of  gravity  would 
cause  them  to  be  traversed  at  a  constant  pace. 
The  apparent  daily  motion  of  the  same  body,  as 
seen  from  the  sun,  would  be  always  the  same.  Is 
it  so  in  the  case  of  any  member  of  the  system  ? 
In  no  single  case,  whether  of  comets  or  planets. 
In  that  of  the  earth,  its  apparent  daily  motion 
as  seen  from  the  sun  —  which  is  the  same  as  that 
of  the  sun  as  seen  from  the  earth  —  is  observed  to 
be  quite  unequal.  It  is  also  noticed  that  there  is 
a  variation  in  the  apparent  diameter  of  the  sun 
in  the  course  of  the  year ;  showing  that  we  are 
at  greater  distances  from  it  at  some  times  than  at 


SHAPES  AND  INCLINATIONS  OF  ORBITS.   113 

others.  So  we  both  satisfy  ourselves  that  our 
orbit  is  an  ellipse,  and  can  tell  just  how  elliptical 
it  is.  To  find  the  exact  form  of  the  other  orbits, 
and  their  inclinations  if  any,  to  our  own,  we  can 
manage  thus.  You  know  that,  if  Cuvier  found  a 
single  bone  of  an  animal,  he  could  build  up  the 
whole  creature  and  picture  it  to  you  in  just 
the  size  and  shape  with  which  it  walked  the 
earth  twenty  thousand  years  ago.  In  a  similar 
manner,  astronomers  can,  from  a  small  piece  of 
an  orbit,  build  up  the  entire  thing  for  us  just  as 
it  stands  in  nature  ;  give  us  its  exact  shape  and 
size  and  bearing  in  space,  in  fact,  a  perfect  fac- 
simile. Any  piece  that  you  can  cut  out  of  a 
given  circle  will  not  fit  any  other  circle,  or  any 
other  curve  line  whatever.  Each  kind  of  curve, 
and  each  specimen  of  a  given  curve,  has  its  own 
law  of  curvature.  The  problem,  then,  is  to  get  a 
true  piece  of  each  orbit  —  to  find  the  single  bone 
from  which  to  reconstruct  the  mastodon.  If  you 
could  only  place  yourself  at  the  sun,  and  draw 
innumerable  lines  of  known  length  to  points  oc- 
cupied successively  by  a  planet,  you  could  by  con- 
necting the  extremities  of  these  lines  get  its  real 
path.  Now  this  you  can  do,  in  effect,  by  finding- 
its  apparent  daily  motion,  as  seen  from  the  earth, 
at  two  times  sufficiently  apart  to  give  you  a  sen- 
sible difference  between  the  motions  ;  also  care- 
fully noting  the  amount  and  direction  of  the 
motion  during  the  interval.  These  elements,  re- 


114  FOURTH  LECTURE. 

duced  to  what  they  would  seem  at  the  sun,  have 
certain  definite  mathematical  relations  to  the  lines 
desired,  by  means  of  which  they  may  be  drawn  to 
any  extent,  and  so  the  astronomer  maps  down  a 
section  of  the  orbit  just  as  it  stands  in  nature. 
Thus  standing,  that  bit  of  a  curve  has  wrapped 
up  in  it  all  the  characteristics  of  the  entire  orbit, 
and  they  may  be  pressed  out  of  it  by  the  hydraul- 
ic press  of  rigorous  mathematics.  You  may  press 
out  of  it  the  eccentricity,  the  inclination  to  our 
orbit,  the  place  of  intersection,  the  place  of  near- 
est approach  to  the  sun.  In  this  way  we  can  find 
that  all  the  planetary  orbits  are  ellipses,  differing 
but  little  from  circles,  and  all — those  of  the  aste- 
roids excepted  —  lying  in  nearly  the  same  plane  ; 
while  the  comets  revolve  on  ellipses  of  great  ec- 
centricity, which  lie  across  the  orbits  of  the  planets 
and  incline  to  them  at  all  angles.  In  some  few 
instances  the  broken  pieces  of  cometary  orbits 
have  seemed  to  belong  to  parabolas  instead  of. 
ellipses  ;  but  the  observations  were  too  rough  to 
be  reliable.  If  parabolas,  the  bodies  traversing 
them,  on  going  away  from  the  sun,  would  never 
return. 

Observation  shows  that  all  the  planets,  and  all 
their  satellites,  excepting  those  of  Uranus,  revolve 
in  the  same  direction,  from  west  to  east.  The 
comets  are  not  at  all  particular  about  following 
this  example.  Having  set  up  in  business  on  a 
principle  of  eccentricity,  each  goes  off  about  the 
BUD  in  the  direction  that  pleases  him. 


SIZES  OF  SUN  AND  PLANETS.  115 

How  large  are  these  astronomical  neighbors 
and  companions  of  ours  —  this  sun,  these  planets, 
these  comets,  most  of  whom  look  so  small  ?  Have 
we  been  spending  our  time  in  considering  the 
order  and  periods  and  distances  and  orbits  of 
what,  after  all,  are  scarcely  more  than  rounded 
pebbles  ?  Having  already  found  the  size  of  the 
earth  to  be  something  considerable,  we  have  a 
curiosity  to  see  how  it  compares  with  that  of  our 
fellow-travelers  about  the  sun,  as  well  as  with 
that  of  the  monarch  himself.  Are  we  so  much 
larger  than  them  all  that  we  can  plume  ourselves  ; 
so  much  larger  as  to  give  color  to  the  ancient 
notion  that  the  axis  of  the  earth  is  the  axle  of 
the  universe  ?  The  fact  that  the  earth  is  not  the 
center  of  the  system  discourages  the  idea,  Also 
these  tremendous  distances  from  us  at  which  our 
Admiral  Sun  is  anchored  and  his  subalterns  sail, 
taken  in  connection  with  the  appreciable  discs 
which  most  of  them  show  in  the  field  of  the  tele- 
scope, give  us  still  further  inkling  that  they  must 
be  bodies  of  extreme  magnitude.  But  let  us 
reduce  the  matter  to  figures.  How  large  does 
the  diameter  of  the  sun  appear  to  the  eye  ?  So 
many  minutes  and  seconds.  What  is  its  distance 
from  us  ?  So  many  miles.  With  these  data,  a 
single  proportion  and  a  single  triangle  give 
442,840  miles  for  the  real  diameter  —  making  a 
space  within  which  might  nearly  be  described  the 
whole  orbit  of  the  moon.  This  makes  our  astron- 


116  FOV  ?T//  LECTURE. 

omical  chief  one  and  a  half  million  times  larger 
than  ourselves.  A  very  Ca3sar  and  Charlemagne  ! 
The  process  for  those  of  the  planets  which 
have  appreciable  discs,  as  well  as  for  all  the 
comets,  is  the  same ;  only  we  have  to  reduce  the 
apparent  diameters  at  the  earth  to  what  they 
would  be  at  the  sun,  in  order  to  use  the  mean 
distances,  which  are  always  given  from  the  center 
of  the  system.  Thus  we  get  the  following  real 
diameters,  in  round  numbers :  of  Mercury,  three 
thousand  miles ;  of  Venus,  eight  thousand ;  of 
Mars,  four  thousand ;  of  Jupiter,  eighty-nine  thou- 
sand ;  of  Saturn,  seventy-nine  thousand  ;  of  Ura- 
nus, thirty-five  thousand  ;  of  Neptune,  thirty-one 
thousand.  As  the  asteroids  have  no  apparent 
discs,  we  do  not  know  precisely  their  size ;  but, 
knowing  their  distances,  we  can  make  certain  that 
none  of  them  exceed  one  hundred  and  sixty  miles 
in  diameter.  They  are  the  infants  of  the  plane- 
tary family  —  the  fledglings  of  the  planetary  flock 
—  the  pinnaces  and  nautiluses  of  the  planetary 
fleet.  As  to  the  comets ;  they  are  of  all  sizes, 
from  mere  specks  of  a  score  of  miles  across,  to 
such  a  mighty  cloud  as  the  great  comet  of  1811 
with  its  head  of  947,000  miles  in  diameter,  and 
train  of  one  hiwidrcd  and  thirty-two  millions  in 
length.  However,  the  same  comet  varies  exceed- 
ingly in  size,  expanding  as  it  approaches  the  sun 
and  contracting  as  it  retires  into  the  frosty  sub- 
urbs of  the  system. 


VELOCITIES  OF   PLANETS.  117 

So  we  see  that,  while  many  of  our  astronomical 
neighbors  are  smaller  than  the  earth,  some  of 
them  are  vastly  larger  —  so  much  larger  that 
the  earth  is  a  mere  babe  by  the  side  of  them. 
But  we  must  not  fall  out  of  conceit  with  our 
little  planetary  home.  The  bulkiest  bodies  are 
not  always  the  best.  The  largest  homes  are  not 
always  the  happiest.  The  largest  empires  are 
not  always  the  most  prosperous,  or  powerful  even. 
Would  you  see  a  famous  land  ?  Look  to  little 
Greece,  and  not  to  mammoth  China.  Would 
you  see  a  theater  of  great  actions  and  sublime 
events  ?  Look  to  little  Thermopyla3,  and  little 
Austerlitz,  and  little  Calvary  —  not  to  New  York 
nor  London.  Still,  it  does  undoubtedly  tend  to 
modesty  in  us  to  compare  the  narrow  limits  of 
our  present  abode  with  the  magnificent  propor- 
tions of  such  planets  as  Saturn  arid  Jupiter,  and 
especially  of  the  tremendous  sun !  We  are 
obliged  to  confess  ourselves  and  our  home  mere 
atoms.  And  if  we  are  so  happy  and  so  philo- 
sophic as  to  have  a  religious  turn  of  mind,  per- 
haps we  shall  bow  our  heads  and  say,  "  What  is 
man  that  Thou  art  mindful  of  him  !  " 

See  now  the  wonderful  velocities  that  must 
prevail  among  some  of  these  great  bodies  !  Know- 
ing their  mean  distances  from  the  sun  and  their 
periods,  we  readily  calculate  their  average  hourly 
pace  on  their  orbits.  Mercury  moves  one  hun- 
dred and  nine  thousand  miles  an  hour,  Venus 


118  FOURTH  LECTURE. 

eighty  thousand,  Earth  sixty-eight  thousand,  Nep- 
tune eleven  thousand,  the  comet  cf  1680,  at 
its  fastest,  eight  hundred  and  eighty-four  thou- 
sand miles  an  hour.  We  have  wondered  at  the 
great  pace  of  the  eagle,  of  the  winds,  of  the  can- 
non-ball, of  the  moon  with  her  fifty-four  thou- 
sand miles  a  day  ;  and  yet  the  moon,  on  her 
monthly  journey  about  us,  is  but  an  indifferent 
traveler  compared  with  the  most  leisurely  of  the 
planets.  They  all  seem  as  if  on  some  urgent 
errand  —  some  errand  of  life  and  death.  When 
one  is  resting  his  weary  body  from  a  third  to  a 
half  of  his  whole  time,  and  happens  to  think  of 
the  tremendous  and  remorseless  activity  of  those 
great  revolving  spheres,  he  is  discontented  with 
himself.  What  miraculous  fleetness !  What  if 
those  flying  orbs  should,  through  some  want  of 
balance  in  the  system,  encounter  each  other  in 
mid-heaven  ! 

We  weighed  off  the  earth  against  a  Scottish 
mountain.  We  weighed  off  the  moon  against  the 
earth,  by  means  of  the  tides.  Can  we  not  also 
weigh  the  other  planets,  and  even  the  sun  itself, 
in  some  great  astronomical  balance  ?  Yes  :  one 
of  the  easiest  things  in  the  world — at  least  so  far 
as  the  sun  is  concerned.  And,  first,  we  may 
weigh  the  sun,  as  we  did  the  moon,  by  means  of 
the  tides.  Another  method  is  by  comparing  the 
curvatures  of  the  terrestrial  and  lunar  orbits. 
In  this  way,  we  really  compare  the  attractions  of 


MASSES  AND  DENSITIES.  119 

the  sun  and  earth  at  different  distances ;  for,  of 
course,  the  degree  of  curvature  depends  on  the 
force  of  gravity  at  the  center.  A  simple  propor- 
tion will  then  compare  their  attractions  —  that  is 
to  say,  their  quantities  of  matter  —  at  the  same 
distance ;  since  they  vary  inversely  as  the  squares 
of  the  distances.  In  this  way  we  may  'find  that 
the  sun  has  three  hundred  and  fifty-two  thousand 
times  the  earth's  quantity  of  matter.  It  would 
weigh  down  three  hundred  and  fifty  thousand 
earths !  *The  philosopher  sits  with  scales  in  his 
hands  —  as  Homer  says  Jupiter  did  on  Ida,  to 
weigh  the  contending  fates  of  Greece  and  Troy. 
He  puts  the  earth  into  one  scale,  and  rolls  the 
sun  into  the  other.  Instantly  the  earth  flies  aloft 
with  tremendous  precipitation.  He  throws  in 
two  worlds  like  ours  —  ten  —  one  hundred  —  one 
thousand  —  with  scarcely  better  success.  In  a  fit 
of  impatience,  he  trundles  all  the  earths  he  has 
into  the  capacious  scallop.  At  last  an  equipoise 
seems  establishing :  the  scales  hang  see-sawing  ; 
and,  at  last,  settle  into  motionlessness  at  the  same 
level.  With  mingled  curiosity  and  astonishment 
he  counts  up  those  terrestrial  globes,  and  finds 
them  three  hundred  and  fifty-two  thousand  in 
number.  Knowing  the  quantity  of  matter  in  the 
sun  and  its  size,  we  can  find  its  density,  or  rela- 
tive compactness  of  matter,  to  be  only  one-quarter 
that  of  the  earth.  In  a  similar  way,  we  may  find 
the  masses  and  densities  of  all  the  planets  that 


120  FOURTH  LECTURE. 

have  satellites  with  orbits  of  known  dimensions. 
As  to  those  planets  which  have  no  such  satellites, 
their  masses  are  known  from  their  effect  in  dis- 
turbing the  motions  of  their  nearest  planetary 
neighbors.  For  example,  compare  the  curve 
which  the  earth  when  nearest  Venus  actually  de- 
scribes with  that  we  should  describe  in  case 
Venus  exerted  no  attraction  on  us,  and  we  have 
a  measure  of  her  attracting  power  or  quantity  of 
matter.  So  of  the  rest.  In  these  ways  we  can 
reach  the  following  results.  Jupiter  and  Uranus 
have  about  the  density  of  water ;  Mercury,  Venus, 
Earth,  Mars,  a  density  from  five  to  six  times 
greater ;  while  Saturn  and  Neptune  have  scarcely 
more  than  one-tenth  of  the  solidity  of  our  own 
globe.  Though  comets  are  so  numerous  —  mil- 
lions, in  fact  —  and  some  of  them  occupy  such 
immense  spaces,  the  quantity  of  matter  in  the 
total  of  them  is  exceedingly  small ;  estimated  by 
careful  men  at  only  -g-oVo"  °^  ^na^  contained  in 
the  earth.  You  can  see  stars  through  their 
trains,  and  sometimes  through  the  very  nuclei. 
They  have  sometimes  passed  very  near  to  planets 
without  sensibly  disturbing  their  motions.  They 
are  mere  planetary  fogs.  And,  summing  up,  it 
appears  that  the  sun  contains  more  than  eight 
hundred  times  as  much  matter  as  all  the  ether 
members  of  the  system  put  together. 
•  All  the  orbits  of  our  system  are  continually 
undergoing  small  changes,  through  the  mutual 


PER  TURB.L  TIONS.  121 

attractions  of  its  various  members.  They  ex- 
pand, they  contract,  they  rock,  they  turn  com- 
pletely round  in  the  same  plane,  their  points  of 
intersection  with  our  orbit  travel  round  through 
the  whole  circumference  of  the  heavens.  This 
fact  gave  rise,  years  ago,  to  much  perplexity, 
many  hard  problems,  many  grave  fears.  It  was 
feared  that  these  gradual  changes  might  so  com- 
bine and  accumulate  in  process  of  time  as  to 
throw  the  whole  system  into  disorder  and  wreck, 
dashing  planets  against  planets  in  hideous  con- 
cussion and  disaster.  At  last  the  great  geometers 
Euler,  La  Place,  and  La  Grange,  undertook  to 
settle  mathematically  whether  the  changes  in  the 
orbits  were  of  such  a  nature  as  to  conduct  to 
such  a  deplorable  issue.  At  last  the  mighty 
problem  stood  resolved.  It  was  found  that,  in 
the  particular  case  where  the  central  body  of  a 
system  is  vastly  heavier  than  all  the  rest,  and  all 
the  planetary  orbits  nearly  circular,  and  nearly 
in  the  same  plane,  and  traversed  in  the  same 
direction  —  all  of  which  features,  as  we  have 
seen,  belong  to  our  system  —  there  are  two 
things  about  every  orbit  that  can  never  change ; 
viz.,  the  greater  axis  and  the  period.  For  exam- 
ple, our  mean  distance  from  the  sun,  as  found 
for  a  single  revolution,  can  never  vary  ;  nor  can. 
the  length  of  our  true  year.  Next,  it  was  proved 
that  in  such  a  system  all  the  changes  that  do 
occur  must  be  periodical,  flowing  and  ebbing  like 


122  FOURTH  LECTURE. 

the  tides  of  the  sea  —  enlarging  for  perhaps  mil- 
lions of  years,  and  then  returning  to  the  old 
point.  So  the  stability  of  the  system  stands  de- 
monstrated. It  has  in  itself  no  seeds  of  death. 
The  invisible  bonds  of  the  law  of  gravity  hold  the 
amazing  leviathans  of  the  sky  so  strongly  and 
surely  that  they  can  not  escape  from  their  spheres. 
The  system  was  built  capable  of  standing  for  ever. 
And  yet  how  easily  it  could  have  been  otherwise  ! 
Suppose  the  sun  had  not  been  made  vastly  heavier 
than  all  the  other  bodies  ;  suppose  Deity  had 
not  so  tempered  the  projectile  force,  in  amount 
and  direction,  to  the  force  of  gravity  of  each 
planet  as  to  make  it  describe  nearly  a  circle ; 
suppose  he  had  shot  off  the  planets  at  all  sorts 
of  angles  with  reference  to  each  other  —  and  he 
might  have  done  each  of  these  things ;  indeed  it 
required  care  not  to  do  them  —  then  the  system 
would  have  been  unstable,  and,  sooner  or  later, 
our  whole  Congress  of  worlds  would  have  gone 
plunging  together  in  frightful  and  unutterable 
catastrophe. 


V. 

HIGHER    SYSTEMS. 


123 


V.    HIGHER  SYS:  EMS. 


1.  SUN  SYSTEMS 125 

2.  GROUP  SYSTEMS 137 

3.  CLUSTER  SYSTEMS 138 

4.  NEBULA   SYSTEMS ...  140 

5.  ULTERIOR  SYSTEMS         ........  146 

6.  ULTIMATE  SYSTEM  .  148 


124 


I 
FIFTH    LECTURE. 


HIGHER  SYSTEMS.    '. 

AS  an  example  of  the  Satellite  Systems,  I  have 
described  the  earth  and  the  moon.  As  an 
example  of  the  Planet  Systems,  I  have  described 
our  sun  with  its  revolving  planets  and  comets. 
We  come  now  to  systems  of  the  Third  Order  — 
Sun  Systems  —  each  of  which  consists  of  two  or 
more  planet  systems  revolving  about  their  com- 
mon center  of  gravity. 

More  than  six  thousand  fixed  stars,  so  called, 
that  appear  single  to  the  naked  eye  or  to  some 
powers  of  the  telescope,  are  found  to  consist,  each 
of  several  stars,  when  proper  glasses  are  brought 
to  bear  upon  them.  Some  are  double,  some  triple ; 
and  in  one  case  six  stars  are  found  to  make  up 
what  appears  a  single  star  to  the  unassisted  eye. 
The  list  of  these  compound  stars  enlarges  every 
year.  Recently,  a  very  important  addition  has 
been  made  to  the  list  by  the  discovery  that  great 
Sirius,  the  glory  of  our  winter  nights,  is  double. 

125 


126  *     FIFTH    \ECTURE. 

An  American  lias  the  honor  of  this  discovery,  and 
of  receiving  for  it  the  La  Lande  prize  from  the 
French  National  Institute. 

It  is  to  certain  of  the  double  stars  that  I  would 
first  ask  your  attention.  Look  at  the  bright  star 
Castor.  Had  you  a  good  telescope  bearing  on  it, 
you  would  find  it  to  consist  of  two  nearly  equal 
members.  And,  could  you  follow  from  year  to 
year  the  bearings  of  these  two  members  with  re- 
spect to  each  other,  you  would,  in  time,  find  one 
of  them  in  course  of  revolution  about  the  other  — 
just  as  the  moon  is  about  the  earth,  and  the  earth 
about  th6  sun.  What  does  this  mean  ?  Why,  it 
means  one  sun  with  its  attendance  of  planets  re- 
volving around  another  sun  with  its  attending  plan- 
ets. That  these  stars  in  Castor  are  self-luminous 
bodies  we  know  from  the  character  of  their  light, 
as  well  as  from  the  impossibility  that  bodies  shin- 
ing by  mere  reflection  of  light  from  our  remote 
sun  or  from  any  neighboring  star  equally  remote, 
should  be  visible  at  such  vast  distances  from  us 
as  all  the  fixed  stars  must  be.  That  each  of 
these  suns  is  the  center  of  a  planetary  cohort 
that  brilliantly  escorts  him  on  his  way,  we  infer 
from  the  analogy  of  our  own  system  and  from  the 
wisdom  of  the  Creator.  When  we  see  a  lamp  in 
a  house,  we  infer  the  neighborhood  of  some  per- 
sons who  need  the  light ;  when  we  see  the  pier- 
cing Fresnel  blaze  of  the  light-house  pouring  far 
and  wide  across  the  darkling  seas,  we  believe  in 


SUN  SYSTEMS.  127 

roving  ships  to  be  guided  and  benefited  by  it ; 
and  when  we  lift  our  eyes  to  where  a  sun  blazes 
as  a  celestial  Eddystone  through  pitchy  space,  we 
conclude  that  there  are  bodies  needing  to  be 
lighted  and  cheered  by  its  beams,  just  as  the  bodies 
of  our  planet  system  need  to  be  lighted  and 
cheered  by  our  solar  orb.  Thus  we  have  a  new 
and  higher  order  of  systems  for  our  astronomy. 
Behold  a  sun  revolving  about  a  sun,  a  planet  sys- 
tem about  a  planet  system ;  necessarily,  two  planet 
systems  about  their  common  center  of  gravity. 

Now  more  than  a  hundred  such  pairs  of  stars 
have  been  caught  in  the  act  of  revolution.  The 
Pole  Star  is  one  of  them.  A  famous  star  in  the 
Constellation  of  the  Swan,  known  as  61  Cygrii, 
is  another.  In  the  case  of  some  of  these  stars,  a 
complete  revolution  has  been  accomplished  since 
attention  was  directed  to  them ;  in  one  case,  two 
full  revolutions  have  been  completed.  But  these 
revolving  suns  are  not  confined  to  sets  of  two. 
There  are  sets  of  three,  of  four,  of  more  stars  — 
in  each  of  which  the  members  have  about  the  same 
brightness  and  distance  from  each  other,  and  are 
in  the  course  of  years  observed  describing  curved 
lines  among  themselves.  Evidently,  more  systems 
of  the  third  order  —  suns  with  their  escorts  of 
planets  revolving,  without  any  intermediate  mo- 
tions, about  their  common  center  of  gravity.  In 
addition  to  these  systems  whose  revolutions  we 
see,  there  are  multitudes  of  others  whose  revolu- 


128  FIFTH  LECTURE. 

tions  we  cfo  not  see,  on  account  of  their  distance 
or  slowness  ;  but  of  which  we  are  just  as  certain 
as  if  we  saw  them.  Since  the  beginning  of  the 
century,  has  ripened  one  of  the  most  important  of 
the  sciences,  under  the  name  of  the  Calculus  of 
Probabilities  —  a  branch  of  that  subtle  and  power- 
ful Differential  and  Integral  Calculus  which  has 
served  the  Prosperos  of  astronomy,  not  only  to  put 
a  girdle  around  the  earth,  but  also  around  the 
whole  visible  heavens.  According  to  this  science, 
there  is  no  chance  worth  considering,  that  any  stars, 
optically  so  close  together  as  to  appear  -single  to 
the  naked  eye,  are  not  actual  neighbors  in 
space,  and  so  in  course  of  mutual  revolution. 
This  principle  gives  us  more  than  a  thousand  ad- 
ditional sun-systems.  But  these  are  not  all. 
Many  stars  that  do  not  appear  single  to  the  naked 
eye  are  proved  to  constitute  similar  systems,  by 
the  identity  of  what  are  called  their  proper  mo- 
tions. Thousands  of  stars  are  found  creeping 
along  the  sky,  not  on  curves,  but  on  straight  lines. 
The  progress  is  exceedingly  slow  —  scarcely  aver- 
aging more  than  y^^oo"  °f  tne  moon's  apparent 
diameter  per  annum.  Now,  whether  this  is  due 
to  our  own  motion,  or  to  that  of  the  stars  them- 
selves, or  to  both,  it  could  not  be  the  same  both 
in  amount  and  direction,  in  the  case  of  two  or 
more  optically  near  stars,  without  their  being 
actually  near  each  other  in  space,  and  so  forming 
a  mutually  revolving  system.  This  principle  en- 


SUN-SYSTEMS.  129 

ables  us  to  make  another  large  addition  to  the 
number  of  our  sun-systems.  Yonder  are  Mizar  and 
Alcor,  two  stars  in  the  tail  of  the  Great  Bear, 
more  than  a  third  of  the  moon's  diameter  apart, 
which  are  thus  proved  to  compose  a  sun-system. 
They  are  creeping  across  the  sky  in  company ; 
going  in  just  the  same  direction,  and  at  just  the 
same  pace.  From  satellite  neighborhoods  we 
have  risen  to  planet  neighborhoods  ;  and  now, 
from  these,  we  have  evidently  risen  to  grand  solar 
neighborhoods,  where  orbed  suns  go  grandly 
wheeling  about  suns,  carrying  with  them  in  insep- 
arable union  their  glittering  retinues. 

How  far  from  us  are  these  sun-systems  ?  At 
one  time  astronomers  almost  despaired  of  being 
able  to  answer  this  question.  They  found  that 
the  method  used  for  finding  the  distances  of  the 
moon  and  sun  from  us  would  not  apply  to  the 
fixed  stars.  No  change  in  our  place  on  the  earth, 
though  it  has  a  diameter  of  eight  thousand  miles, 
caused  the  slightest  change  in  the  apparent  place 
of  any  of  those  twinkling  points.  If  we  could 
only  travel  off  two  or  ten  times  eight  thousand 
miles  on  a  straight  line  !  Well,  can  you  not  — 
do  jaou  not  ?  Do  you  not,  every  year  of  your  life, 
make  a  vastly  greater  travel  than  that  ?  Is  not 
the  earth  sailing  away  with  you  about  the  sun  at 
the  rate  of  sixty-eight  thousand  miles  an  hour, 
and  so  at  the  ends  of  every  six  months  putting 
you  at  the  opposite  extremities  of  a  straight  line 


130  FIFTH  LECTURE. 

one  hundred  and  ninety  millions  of  miles  long  ? 
So  observers  set  themselves  to  see  whether  such  a 
monster  base  line  as  the  diameter  of  the  earth's 
orbit  would  make  any  impression  on  the  places 
of  the  fixed  stars.  Their  triangles  informed  them 
that  in  case  a  star  should  be  displaced  on  the  sky 
less  than  the  eighteen-hundredth  part  of  tho 
moon's  apparent  breadth,  by  their  going  that  im- 
mense distance,  it  must  be  more  than  one  hun- 
dred thousand  times  that  distance  from  them. 
And  they  could  not  find  any  star  that  showed  a 
clear  annual  displacement  of  even  that  small 
amount.  So  they  put  up  their  bulletin,  and  in- 
formed the  world  that  no  fixed  star  could  be 
nearer  to  us  than  one  hundred  thousand  times  one 
hundred  and  ninety  millions  of  miles.  A  most 
bewildering  distance  !  It  would  take  light  itself, 
that  fleetest  of  known  travelers,  that  Mercury  of 
science,  whose  pace  is  one  hundred  and  ninety- 
two  thousand  miles  a  second,  more  than  three 
years  to  sweep  across  it.  Here  it  was  feared  our 
knowledge  must  end.  We  could  tell  the  point 
from  us  within  which  the  fixed  stars  could  not  be  ; 
but  their  actual  distances,  who  could  ever  know  ? 
But  Providence  was  kind.  It  gave  the  world,  at 
length,  a  Bessel  to  bridge  over  that  tremendous 
chasm  between  us  and  the  sun-systems  of  remote 
space,  and  set  up  mile-stones  along  it  —  a  man 
who  found  himself  able  to  measure  a  smaller  bit 
of  the  sky  than  one  second,  who  found  that  by 


SUBSYSTEMS.  131 

management  he  could  make  sensible  in  his  as- 
tronomy even  so  trifling  a  fraction  as  the  thou- 
sandth part  of  a  second  —  a  man  who  could  not, 
indeed,  like  one  of  his  countrymen,  write  him- 
self, "  By  the  grace  of  God,  King  of  Prussia,"  but, 
what  was  far  better,  who  could  write  himself, 
"  By  the  grace  of  God,  King  of  Prussian  astron- 
omers." He  found  that,  by  going  over  the  whole 
diameter  of  the  earth's  orbit,  one  would  alter  the 
apparent  place  of  the  double  star  61  Cygni  about 
one-third  of  a  second.  This  makes  its  distance 
from  us  three  hundred  thousand  times  one  hun- 
dred and  ninety  millions  of  miles  —  an  interval 
which  it  takes  light  nine  years  to  traverse. 

This  was  in  1838.  Since  then,  about  forty  stars 
have  yielded  up  their  distances  from  us  to  our 
curiosity.  The  nearest  sun-system  yet  found  be- 
longs to  the  southern  hemisphere  —  Alpha  Cen- 
tauri,  the  brightest  star  in  the  Centaur,  and  in- 
deed in  the  whole  southern  vault.  This  is  only 
one-third  as  remote  as  61  Cygni.  The  Pole  Star 
system,  on  the  other  hand,  is  five  times  as  remote 
—  one  million  five  hundred  thousand  times  one 
hundred  and  ninety  millions  of  miles.  The  mar- 
iner and  the  fugitive  have  used  light  to  guide 
them  on  their  way  which  has  been  forty-six  years 
in  coming  to  them  for  that  purpose. 

One  would  like  to  know  how  large  these  re- 
volving suns  are  ;  how  they  compare  in  this  re- 
spect with  our  sun.  If  they  showed  real  diame- 


132  FIFTH  LECTURE. 

ters  under  the  telescope,  we  could  at  once  make 
the  comparison.  But  they  do  not.  So  we  are 
driven  to  another  method  of  a  less  satisfactory 
kind,  but  still  one  that  will  help  us  to  some  just 
idea  of  how  the  different  suns  of  space  compare 
with  each  other  in  magnitude.  Delicate  instru- 
ments have  been  invented  for  measuring  the  rel- 
ative amounts  of  light  from  the  heavenly  bodies. 
With  what  is  perhaps  the  best  of  these  instruments, 
it  is  concluded  that  we  receive  twenty-two  thousand 
million  times  the  light  from  our  sun  that  we  do 
from  the  sun-system  Alpha  Centauri.  But  that  sys- 
tem is  two  hundred  thousand  times  further  away. 
Hence  it  follows,  that,  if  it  were  brought  as  near  to 
us,  it  would  give  a  little  more  than  twice  as  much 
light  as  our  sun  ;  that  is,  each  of  the  two  nearly 
equal  suns  that  compose  the  star  is  about  equiva- 
lent, in  the  matter  of  light,  to  our  luminary.  In  the 
same  way  we  find  that  the  61  Cygni  system  gives 
about  half  as  much  light  as  our  sun  ;  making 
each  of  its  two  nearly  equal  members  equivalent 
to  a  quarter  of  our  sun.  The  Sirius  system  is 
equal  in  light  to  sixty-three  of  our  suns  ;  the  Pole- 
Star  system  to  eighty-six.  In  each  of  these,  the  two 
stars  composing  the  system  differ  exceedingly 
from  each  other  in  brightness,  and  the  larger  star 
must  be  credited  with  most  of  the  brilliancy. 
Think  of  an  eighty-fold  sun  !  However,  some 
stars  are  still  more  astonishing ;  Vega,  for  ex- 
ample, which  blazes  with  the  light  of  three  him- 


SUN-SYSTEMS.  »      133 

dred  and  forty-four  suns  ;  Capella,  for  example, 
which  blazes  with  the  light  of  four  hundred  and 
thirty  ;  Arcturus,  for  example,  which  blazes  with 
the  light  of  five  hundred  and  sixteen  ;  Alcyone, 
for  example,  which  blazes  with  the  light  of  twelve 
thousand  !  As  we  have  seen,  our  sun  is  no  trifle. 
Its  astonishing  orb  would  nearly  fill  the  whole  lu- 
nar orbit ;  and  would  weigh  down,  eight  hundred 
times  over,  its  whole  ponderous  cortege  of  satel- 
lites, planets,  and  comets.  And  yet  it  is  only  one 
of  the  lesser  lights  of  space.  Not  the  smallest,  in- 
deed —  forbid  it,  little  61  Cygni  —  but  still  a 
mere  rush-light  and  glow-worm  as  compared  with 
many  of  the  huge  luminaries  which  pour  their 
glories  adown  the  immensity  of  nature.  It  could 
not  remain  visible  a  moment  in  the  presence  of 
such  golden-haired  and  majestic  day-kings  as  even 
Sirius  and  Polaris  to  say  nothing  of  those  huger 
monarchs  whose  effulgence  floods  the  celestial 
spaces. 

Knowing  the  distance  of  one  of  the  systems 
from  us,  we  can  find  how  far  apart  its  members 
are  at  any  time,  by  observing  the  apparent  dis- 
tance between  them.  The  two  suns  of  Alpha 
Centauri  are  apart  by  only  seven  diameters  of  the 
earth's  orbit  —  something  less  than  the  distance 
of  Uranus  from  our  sun  —  so  that  planets  belong- 
ing to  the  system  will  sometimes  have  two  suns 
above  the  horizon  at  once,  while  at  another  time 
one  sun  will  rise  while  the  other  sets.  The  two 


134        •  FIFTH  LECTURE. 

suns  of  61  Cygni  are  apart  by  twenty-one  diame- 
ters of  our  orbit ;  those  of  the  Pole  Star  by  one 
hundred  and  five  diameters  ;  Mizar  and  Altfor  by 
at  least  five  thousand  diameters  —  five  thousand 
times  one  hundred  and  ninety  millions  of  miles  — 
a  line  on  which  could  be  ranged  three  hundred 
and  sixty  planet-systems  like  ours. 

Several  of  these  systems  having  made  entire  rev- 
olutions since  they  began  to  be  scrutinized,  we  may 
be  said  to  have  seen  their  periods.  Others  have 
advanced  so  far  on  their  orbits  that  we  can  readily 
estimate  the  times  required  to  accomplish  the  re- 
mainders. And  others  still  have  been  under  ob- 
servation sufficiently  long  to  furnish  us  with  very 
considerable  pieces  of  the  curves  they  describe ; 
from  which,  like  the  naturalists,  we  can  build  up 
the  entire  orbits,  and  press  out  of  them  by  our 
powerful  geometry  all  their  characteristics  — 
among  other  things,  the  periods  and  ellipticities. 
The  periods  differ  among  themselves  wonderfully. 
One  is  forty  years  ;  that  of  Alpha  Centauri  is 
seventy-seven  years  ;  that  of  61  Cygni  four  hun- 
dred and  fifty-two  ;  another  three  thousand  ;  and 
that  of  Mizar  and.Alcor  must  be  something  like 
two  hundred  thousand  years  !  Wonderful  year 
of  two  hundred  millenniums  !  Wonderful  orbits 
also,  as  far  as  observed  —  wonderful  for  their  el- 
lipticity  !  In  one  case,  that  of  Alpha  Centauri, 
the  orbit  is  five  times  as  long  as  it  is  broad. 
What  extremes  this  means  may  be  seen  from  the 


SUN-SYSTEMS.  135 

case  of  Halley's  comet.  This  body  has  an  orbit 
four  times  as  long  as  it  is  broad  ;  and  the  con- 
sequence is,  that,  while  at  one  point  it  ap- 
proaches the  sun  as  near  as  Mercury,  at  another 
it  recedes  from  it  six  hundred  millions  of  miles 
beyond  Neptune  —  the  least  distance  from  the  sun 
being  to  the  greatest  as  one  to  eighty-five.  Such 
variations  would  be  fatal  to  an  inhabited  earth  ; 
but  to  a  sun,  that  movable  furnace  that  carries 
its  own  light  and  heat  with  it  wherever  it  goes, 
what  matters  it  how  far  it  strays  off  from  its  cen- 
tral orb  into  the  cold  of  space  —  to  a  sun  that  is 
never  at  less  than  white  heat,  what  matters  it  if  it 
sometimes  gets  a  good  deal  whiter  !  We  may  be 
sure,  however,  that  those  sun-systems  which  con- 
sist of  three  or  more  suns  do  not  contain  such 
eccentric  orbits.  It  would  be  inconsistent  with 
their  stability.  As  our  planet  system  would  fall 
to  ruin  were  not  its  orbits  nearly  circular,  nearly 
in  the  same  plane,  and  controlled  by  a  force  at 
the  common  center  of  gravity  greatly  superior  to 
any  individual  force  in  the  system,  so  would 
every  higher  system  made  up  of  more  than  two 
members. 

Before  dismissing  these  sun-systems,  I  must  say 
a  word  as  to  their  color.  All  the  colors  of  the 
rainbow  are  represented  in  them.  Some  sys- 
tems are  white,  some  blue,  some  red,  some  yellow, 
some  green  ;  and  this,  you  will  observe,  means 
differently  colored  days  for  the  planets  of  those 


136  FIFTH  LECTURE, 

systems.  Castor  gives  bis  planets  green  days. 
The  Pole  Star  gives  his  yellow.  There  are  more 
than  sixty  blue  systems,  one  of  these  consisting 
of  a  great  number  of  members.  In  the  southern 
hemisphere  are  stars,  yet  to  be  found  double, 
which  in  the  telescope  look  like  drops  of  blood  — 
all  about  the  constellations  of  the  Cross  and 
Altar,  as  if  to  gloriously  symbolize  the  sprinkled 
blood  of  our  redemption.  Also  the  suns  of  the 
same  system  often  have  different  colors ;  one 
shining  like  an  emerald,  another  like  a  ruby,  and 
perhaps  a  third  like  a  sapphire.  And,  as  if  to 
make  that  Southern  Cross  the  fairest  object  in  all 
the  heavens,  we  find  in  it  a  group  of  more  than 
a  hundred  variously-colored  red,  green,  blue,  and 
bluish-green  suns,  so  closely  thronged  together  as 
to  appear  in  a  powerful  telescope  like  a  superb 
bouquet,  or  piece  of  fancy  jewelry.  Let  no  one 
say  that  the  Creator,  who  makes  gems  and  flow- 
ers for  the  earth,  and  sets  gems  and  flowers  in 
the  sky,  cares  not  for  natural  beauty :  though 
it  be  most  true  that  the  '  beauties  of  holiness,  es- 
pecially from  the  womb  of  the  morning,  when 
thou  hast  the  dew  of  thy  youth,'  are  still  more 
precious  in  his  sight. 

GROUP-SYSTEMS!  Near  the  bright  blue  star 
Yega  is  a  star  which  the  telescope  finds  to  be 
quadruple.  The  four  stars  are  arranged  in  pairs 
—  the  pairs  being  many  times  further  apart  than 


GROUP-SYSTEMS.  137 

are  the  individuals  of  each  pair.  The  whole 
form  a  system  by  themselves;  as  is  shown  by  the 
sameness  in  amount  and  direction  of  their  proper 
motions.  But,  grouped  as  they  are,  the  law  of 
gravity  requires  each  pair  to  revolve  around  its 
center  of  gravity,  and  then  both  pairs  about  their 
common  center  of  gravity.  The  revolution  is 
not  seen,  as  in  the  case  of  many  double  stars  ;  but 
we  are  just  as  sure  of  its  reality  as  if  we  saw  it. 

In  Orion  is  a  star  which  the  telescope  finds  to 
be  sextuple.  The  six  stars  have  all  the  same 
proper  motion,  and  so  are  neighbors  in  space. 
Four  of  them  are  at  about  the  same  distance  from 
each  other ;  but  two  of  these  have  each  a  small 
companion  much  nearer  to  it  than  are  the  others. 
The  law  of  gravity  requires  each  pair  to  form  a 
revolving  group  by  itself,  and  then  all  the  spheres 
to  wheel  about  the  common  center  of  gravity  of 
the  whole.  That  superb  wheeling  is  not  seen,  on 
account  of  distance ;  but  we  are  just  as  sure  of 
it  as  if  we  saw  it.  Another  Group-system  ! 

Look  at  the  famous  and  beautiful  Pleiades  ! 
Gathered  about  the  brightest  star  of  the  group 
Alcyone,  the  telescope  sees  fourteen  conspicuous 
stars.  These  are  all  creeping  along  the  sky, 
equally  fast  and  in  the  same  direction.  The  cal- 
culus of  probabilities  assures  us  that  the  chances 
are  hundreds  of  millions  to  one  against  their 
being  merely  optically  connected.  They  form 


138  FIFTH  LECTURE. 

one  grand  astronomical  neighborhood  in  space, 
around  whose  center  of  gravity  they  all  revolve ; 
one  grand  company  of  celestial  navigators,  ex- 
ploring their  way  by  unerring  instinct,  without 
chart  or  compass,  through  trackless  space.  But, 
if  you  should  see  a  map  of  these  fourteen  stars, 
you  would  find  them  distributed  into  several 
groups,  each  of  which  must  contain  its  own  cen- 
ter of  revolution,  while  all  these  centers  must  be 
borne  in  majestic  sweep  about  the  gravity-center 
of  the  whole  sparkling  family.  Invisible  or- 
bits within  orbits  ;  but  as  certain  as  if  we  saw 
their  fiery  ellipses  burnt  into  the  dark  concave 
of  evening  !  The  distance  of  this  group-system 
from  us  has  been  determined  by  the  determina- 
tion of  the  distance  of  Alcyone  ;  and  is  twenty-five 
million  diameters  of  the  earth's  orbit.  Were  the 
Pleiades  this  moment  blotted  out  of  existence, 
they  would  still  blaze  away  in  the  neck  of  Taurus 
for  more  than  seven  hundred  years ;  for  that  is 
the  time  spent  by  light  in  passing  from  that  sys- 
tem to  us. 

These  specimens  of  the  group-systems  must 
suffice.  We  pass  to  the  next  higher  order  — 
CLUSTER  SYSTEMS. 

There  are  thousands  of  small  roundish  spots 
on  the  sky  which,  when  examined  by  telescopes, 
prove  to  consist  of  crowded  stars ;  sometimes 
uniformly  distributed  ;  in  other  cases,  gradually 


CLUSTER-SYSTEMS.  139 

becoming  denser  till  all  individuality  is  lost  in  a 
general  blaze  of  light  at  the  center  ;  and  in  other 
cases  still,  arranged  into  several  nuclei  which  lie 
quite  evenly  over  the  mottled  face  of  the  cluster. 
On  examining  the  nuclei  carefully,  they  are  some- 
times found  to  consist,  each,  not  of  a  single  group, 
but  of  a  cluster  of  groups.  Behold  systems  of 
the  Fifth  Order  !  The  artificial  form  of  each  gen- 
eral cluster,  and  the  chasm  of  black  space  all 
around  it,  show  that  it  is  a  system  by  itself  in 
space,  with  its  one  center  of  revolution  for  all  the 
nuclei.  Then  each  nucleus  has  its  own  subordi- 
nate center  for  all  the  groups  composing  it ;  and 
next,  each  group  has  its  still  more  subordinate 
center  for  all  the  suns  composing  it.  Many  of 
these  great  systems  must  contain  from  ten  to 
twenty  thousand  stars  each.  Think  of  a  system 
made  up  of  twenty  thousand  revolving  suns  ;  each 
sun  with  its  planets  occupying  at  the  same  time 
a  three-fold  orbit,  and  spinning  at  once  around 
three  widely  separated  centers  —  first,  around  the 
center  of  the  group ;  next,  around  the  center  of 
its  cluster  of  groups  ;  and  then,  around  the  center 
of  the  whole  great  cluster ! 

As  an  example  of  these  cluster-systems,  I  in- 
stance a  cluster  found  in  the  constellation 
Hercules.  It  is  famous  among  astronomers  as 
being  the  grandest  object  of  its  class  in  the 
whole  heavens.  When  Sir  William  Herschel  saw 
it  for  the  first  time  through  his  great  reflector,  it 


140  FIFTH  LECTURE. 

almost  made  him  leap,  with  mingled  astonishment 
and  delight.  An  eminent  astronomer  doubts 
whether  any  person  ever  saw  it  for  the  first  time, 
through  a  large  telescope,  without  a  shout  of  won- 
der. Certainly  it  is  an  object  of  wonderful  glory, 
—  that  golden  shield  of  packed  suns  !  Shall  we 
call  it  the  segis  of  immortal  Jove  ?  Call  it, 
rather,  the  flaming  buckler  of  the  Christian 
Creator,  hung  out  for  sign  on  heaven's  blue  bat- 
tlements, and  on  whose  thick  bosses  those  men 
insanely  rush  who,  in  the  face  of  the  stars,  pre- 
sume to  doubt  Almighty  God  !  The  first  Herschel, 
sounding  the  heavens  with  his  telescopes,  con- 
cluded this  cluster-system  to  be  deep  in  the 
abyss  several  hundred  times  the  distance  of  the 
nearest  fixed  star —  say  some  two  thousand  years, 
as  light  travels.  Its  locomotive  suns,  with  their 
long  trains  of  planets,  do  not,  at  such  a  distance, 
render  to  our  eyes  those  mighty  three-fold  curves 
on  which  they  are  rushing ;  but  we  are  just  as 
sure  of  their  reality  as  though  we  saw  them  — 
saw  them  as  we  see  the  orbits  of  binary  stars  — 
saw  them  as  we  see  the  track  of  the  rocket  when 
it  describes  its  flaming  parabola  through  the  air. 

We  advance  another  step,  to  systems  of  the 
Sixth  Order,  —  NEBULA  SYSTEMS  ! 

Scattered,  or  rather  arranged,  over  the  sky  by 
thousands  are  those  bright-misty  spots,  called 
nebulae,  which  no  power  of  the  telescope  has  yet 


NEBULA-SYSTEMS.  141 

been  able  to  resolve  into  stars.  It  has  been 
claimed  that  they  do  not  consist  of  stars,  but  only 
of  a  sort  of  fire-mist,  out  of  which  suns  and 
planets  and  satellites  are  in  process  of  being  made 
by  natural  law.  There  are  many  objections  to 
this  view.  But  it  is  enough  that  there  is  not  a 
single  proved  case  of  such  fire-mist  in  space  ;  that 
the  hypothesis  is  altogether  unnecessary  to  ac- 
count for  the  facts  observed  ;  and  that  nebulae, 
apparently  as  irresolvable  as  any,  have,  by  improve- 
ments of  telescopes,  been  turned  into  clusters  of 
stars.  In  my  view,  they  all  consist  of  stars,  so 
packed  together  by  local  neighborhood  and  un- 
speakable distance  that  all  individuality  of  im- 
pression on  the  eye  is  lost.  They  are  found  in 
great  variety  of  singular  and  beautiful  forms  — 
sometimes  perfectly  round,  sometimes  oval,  some- 
times lens-shaped,  sometimes  ring-shaped  and 
even  consisting  of  a  series  of  concentric  rings. 
One  beautiful  nebula  resembles  a  crab  ;  another, 
a  fan  ;  another,  an  hour-glass  ;  another,  a  whirl- 
pool, whose  eddies  are  made  evident  to  the  eye 
by,  as  it  were,  floculi  torn  from  the  famous 
golden  fleece  of  Colchis.  Some  of  them  are 
perfectly  continuous  and  uniform  in  appearance. 
Others  are  "spotted  as  a  pard,"  with  numerous 
centers  of  condensation  :  while  others  still  are 
broken  up  into  more  or  less  distinctly  separated 
nebulous  patches ;  like  a  defeated  army  whose 
great  corps  are  just  in  the  act  of  separating  to- 


142  FIFTH  LECTURE. 

ward  all  points  of  the  compass.  The  great  frag- 
ments of  these  routed  nebulae  appear  in  the  best 
telescopes  very  much  as  the  cluster-systems  do  in 
the  smaller  —  that  is  to  say,  dappled  with  nuclei 
pretty  evenly  distributed.  They  are  evidently 
cluster-systems.  And,  taken  together,  they  form 
a  revolving  neighborhood  in  space,  of  another 
order  still  higher  —  a  Nebula  System  in  which 
nebulaB  of  clusters  of  groups  of  suns  sweep  their, 
at  least,  quintuple  orbits  in  harmonious  combi- 
nation around  the  gravity-center  of  the  whole 
nebula. 

What  is  the  Milky  Way,  so  called,  which  we 
see  belting  our  heavens  ?  Nothing  but  the  nebula 
to  which  we  belong,  expanded  all  round  the  sky 
and  easily  resolved  into  stars  by  the  fact  that  we 
are  in  the  midst  of  it.  A  little  observation  and  re- 
flection suffice  to  show  that  its  shape  is  that  of  a 
thick  mill-stone,  with  its  rim  split  in  the  middle  for 
about  a  third  of  its  length  and  somewhat  opened. 
Our  place  is  near  the  plane  of  this  cleavage,  but 
considerably  one  side  of  the  center.  When  we, 
from  our  place  in  this  cleft  wheel  of  stars,  look 
off  in  the  direction  of  the  circumference,  the  stars 
appear  very  numerous  ;  when  we  look  toward  the 
sides,  we  see  comparatively  few.  All  the  scat- 
tered stars,  all  the  groups,  small  and  large,  that  we 
see  in  any  direction,  belong  to  our  Milky  Way  — 
to  our  nebula.  They  are  nearer  to  us  than  any 
other  stars  in  space.  All  the  stars  whose  dis- 


NEB  ULA-S  YSTEMS.  143 

tances  have  been  determined,  all  the  multiple 
stars  whose  orbits  have  been  observed,  all  the 
stars  whose  proper  motions  have  been  noticed,  are 
as  much  part  of  our  Milky  Way  as  the  milkiest 
part  of  it.  All  the  examples  of  astronomical  sys- 
tems which  I  have  hitherto  given,  at  least  up  to 
the  cluster-systems,  were  from  this  same  nebula 
of  ours.  And  cluster-systems  themselves  can  be 
easily  supplied  from  it.  If  you  will  scan  on  some 
favorable  night  the  remoter  parts  of  this  white 
Wonder,  you  will  find  that  it  is  by  no  means  a 
continuous  nebulous  zone,  but  rather  a  succession 
of  star-clouds,  many  of  which  are  mottled  after  the 
manner  of  the  cluster-systems.  And  such  they 
are.  The  whole,  from  satellites  to  sun-clusters, 
are  in  process  of  revolution  about  the  great  force- 
ful heart  of  the  nebula.  We  know  it  must  be  so, 
in  advance  of  all  observation.  But  in  this  case  it 
is  thought  that  observation  has  made  assurance 
doubly  sure.  First,  our  sun  is  in  motion  —  like 
Castor  and  Polaris  ;  like  the  thousands  of  stars 
that  show  proper  motions,  and,  in  part,  because 
they  show  them.  A  wonderful  thing  has  been 
noticed  in  that  part  of  the  heavens  that  is  now 
passing  over  our  meridian  southward  from  the 
zenith ;  the  region  occupied  by  Orion,  the  river 
Po,  Sirius,  and  especially  the  Dove.  It  has  been 
noticed  that  the  stars  in  this  region  are  gradually 
drawing  together,  just  as  the  ships  of  a  fleet  would 
seem  to  do  to  one  sailing  away  from  them ;  while 


144  FIFTH  LECTURE. 

at  the  opposite  quarter  of  the  sky  the  stars  are 
gradually  separating,  just  as  the  ships  of  another 
fleet  would  seem  to  do  to  one  sailing  toward 
them.  Great  Hercules  is  yearly  becoming  linger 
and  brawnier ;  his  club,  and  especially  his  bow, 
growing  every  year  more  formidable.  This  has 
been  going  on  now  for  a  great  number  of  years. 
Of  course,  there  is  but  one  explanation.  Our 
sun,  with  its  retainer-worlds  about  it,  is  sailing 
away  through  space  toward  Hercules,  on  an  orbit 
so  vast  that  the  part  of  it  which  has  been  described 
from  the  date  of  the  earliest  accurate  observations 
does  not  differ  sensibly  from  a  straight  line.  At 
last,  however,  we  shall  double  the  wondrous  cape 
of  our  great  ellipse  ;  and  then  the  Dove  will  begin 
to  expand  and  plume  her  heavenly  wings,  while 
champion  Hercules  will  dwarf  behind  us.  But 
this  does  not  determine  where  the  center  of  mo- 
tion is.  Where  is  it  ?  Astronomers  have  sought 
to  answer  this  question,  and  apparently  not  in 
vain.  By  methods  which  can  not  now  be  ex- 
plained, it  is  found  that  Alcyone  — most  beautiful 
star  of  the  beautiful  Pleiades — is  the  center  of  our 
motion  ;  and  that  we  are  moving  about  it  at  the 
rate  of  more  than  thirty-three  millions  of  miles  a 
year,  on  an  orbit  whose  diameter  is  fifty  million 
times  larger  than  that  on  which  we  move  about 
the  sun.  As  the  distance  of  Alcyone  is  approxi- 
mately known,  we  can  find  our  period.  It  is  only 
about  twenty  millions  of  years. 


NEB  ULA-S  ? STEMS.  1 45 

Such  is  our  sun's  center  of  motion.  And  the 
celebrated  Maedler  has  shown  that  it  is  also  the 
center  of  a  great  number  of  other  suns  —  in  fact, 
that  the  proper  motions  of  the  stars  in  all  quar- 
ters of  the  heavens  conform  to  the  idea  that  they 
are  spurring  in  glorious  curriculum  around  the 
same  point.  He  concludes  that  Alcyone  is  the 
center  of  the  whole  nebula.  And  though  the 
English  Astronomer  Royal  has  recently  dissented 
from  this  conclusion,  and  though  we  certainly  are 
not  authorized  to  claim  for  it  the  most  absolute 
proof,  yet  it  is  probably  as  much  like  the  truth  as 
most  photographs  are  like  the  persons  who  sit  for 
their  pictures  to  the  sun. 

Mysterious  continental  islands  of  the  remoter 
heavens  !  Greatest  empires  of  suns  that  have 
yet  sent  greeting  light  to  us  !  There  ye  lie  to- 
night, seemingly  steeped  in  breathless  quietude 
and  uttermost  sleep,  where  the  earliest  observer 
saw  you :  and  yet  what  mighty  race-Cvmrses  are 
those  on  which  your  orbs  go  panting  their  eternal 
rounds  about  the  great  nebular  heart !  Why,  let 
us  measure  two  of  these  celestial  Astrodromes. 
According  to  the  best  estimates  of  our  own  neb- 
ula it  contains  some  eighteen  million  suns  ;  and 
the  thickness  of  its  golden  wheel  is  about  eight 
million  diameters  of  the  earth's  orbit,  while  its 
diameter  is  one  hundred  and  seventy  million  such 
diameters.  One  of  its  Border  States  would  re- 
quire not  far  from  one  hundred  millions  of  years 
10 


146  FIFTH  LECTURE. 

to  put  orbit  about  metropolis  Alcyone;  and, 
though  so  remote,  has  never  been  in  danger  of 
parting  company  with  us.  There  is  the  oval  ne- 
bula of  Andromeda,  just  visible  to  the  naked 
eye  and  yet  giving  no  sign  of  resolvability  in  the 
six-foot  speculum  of  the  Earl  of  Rosse.  A  nebula 
of  which  such  things  are  true,  is  easily  shown  to 
be  so  far  away  that  the  light  by  which  we  see  it 
must  show  it  as  it  was  at  least  a  million  of  years 
ago,  instead  of  as  it  is  to-night.  The  rays  have 
been  all  that  time  charging  across  the  void  at  the 
rate  of  192,000  miles  a  second.  At  such  a  dis- 
tance, its  apparent  diameter,  half  that  of  the 
moon,  means  for  the  nebula  a  breadth  of  thirty 
thousand  years  —  the  fifty-three  foot  reflector 
being  surveyor-general,  and  a  light-sprite  carry- 
ing the  chain. 

We  have  found  all  the  suns,  and  groups  of 
suns,  and  clusters  of  groups  of  suns,  in  each  neb- 
ula, engaged  in  revolution  about  its  center  of 
gravity.  Is  this  center  itself  in  motion  on  another 
orbit  still  larger  ?  Is  each  nebular  fleet,  instead 
of  riding  at  anchor  in  the  sky,  sailing  away  on  a 
circumnavigation  more  stupendous  than  any  we 
'  have  yet  noticed  ?  It  is  even  so.  There  are 
ULTERIOR  SYSTEMS.  We  find  nebula  disposed  in 
groups  of  two  or  more  ;  of  about  the  same  bright- 
ness, coming  into  view  with  about  the  same  power 
of  the  telescope  ;  evidently  belonging  to  the  same 
order  of  distances  from  us.  Just  as  there  are 


UL  TERIOR-S  Y STEMS.  1 47 

double  and  multiple  stars,  so  there  are  double, 
triple,  quadruple,  quintuple,  sextuple  nebulae ; 
and  recently  D'Arrest,  a  Danish  astronomer,  has 
announced  that  he  has  actually  caught  a  nebula 
in  the  act  of  revolving  about  a  nebula.  Very 
likely  he  is  mistaken ;  it  seems  as  if  he  must 
be  ;  in  any  event,  we  need  no  such  ocular  dem- 
onstration. We  have  long  been  as  sure  of  re- 
volving nebula3  as  if  we  had  seen  them  —  sure 
of  some  Alcyone,  12,000  suns  strong,  revolving 
about  another  Alcyone,  perhaps  100,000  suns 
strong.  More  than  this.  The  Magellanic  Clouds, 
so  called,  of  the  southern  hemisphere,  are  nothing 
but  two  great  beds  of  clusters  and  nebulas  ;  three 
hundred  nebulae  in  one,  and  thirty-seven  in  the 
other  :  and  in  the  constellation  Virgo,  especially 
in  one  of  its  wings,  the  nebulae  are  scattered  al- 
most as  the  grain  will  be  sown  in  your  fields  this 
spring  —  swarms  of  them,  in  groups  and  clusters 
of  groups  ;  and  it  is  just  as  certain  that  each  of 
these  great  beds  is  in  course  of  revolution  about 
its  center  of  gravity  as  it  is  that  over  that  amaz- 
ing congeries  of  firmaments  is  stretched  the  scep- 
ter of  law. 

Mightiest  of  astronomical  neighborhoods  >et 
seen  !  What  wondrous  outskirting  orbits  have 
we  here  —  what  abysses  of  periods  —  what  year 
Great  and  Wonderful  in  which  some  picket  sun 
of  one  of  those  picket  nebulae  spins  out  its  ellipse 
about  the  whole  nebulous  stratum  to  which  it 


148  FIFTH  LECTURE. 

belongs !  What  abysmal  grandeurs  of  motion 
are  piled  and  compacted  within  that  circle  of  20° 
diameter  about  the  wing  of  Yirgo  !  The  ancients 
did  not  know  what  wonders  were  swarming  in. 
this  region  ;  and,  had  they  known,  they  could 
hardly  have  covered  its  flying  hosts  with  a  more 
appropriate  symbol  than  they  have  done  —  a 
broad  celestial  wing.  You  easily  understand  the 
utter  inadequacy  of  figures,  whether  expressing 
miles  or  diameters  of  the  earth's  orbit  or  the  largest 
measured  distances  of  fixed  stars  or  years  of  light- 
motion  even,  to  express  the  dimensions  of  this 
Titanic  nebular  system. 

Such  are  the  various  orders  of  systems  which 
we  can  prove  to  be  within  the  range  of  our  tele- 
scopes. But  no  astronomer  doubts  that  within 
this  range  may  lie  hundreds  of  different  orders, 
wheel  within  wheel,  in  astounding  climax  and 
bewildering  complexity :  even  that  within  this 
range  our  own  earth  may  be  describing  a  thou- 
sand-fold orbit  about  a  thousand  different  centers. 

But  there  must  be,  at  last,  a  UNIVERSE  SYSTEM 
—  a  system  composed  of  all  the  bodies  that  people 
space,  and  in  which  each  body  revolves  about  the 
gravity-center  of  the  whole  material  universe. 
Let  us  devote  a  few  thoughts  to  it. 

Eighteen  million  suns  belong  to  our  firmament. 
More  than  four  thousand  such  firmaments  are 
visible ;  and  every  increase  of  telescopic  power 
adds  to  the  number.  Where  are  the  frontiers  — 


UNIVERSE-SYSTEM.  149 

the  last  astronomical  system  —  that  remote  spot 
beyond  which  no  nebula,  no  world,  glitters  on  the 
black  bosom  of  eternal  nothingness  ?  Probably, 
some  one  of  those  many  nebulae  just  brought 
into  faint  view  by  the  great  reflector  at  Rosse  Cas- 
tle, is  but  another  nebula  of  Andromeda ;  which, 
though  visible  to  the  naked  eye,  gives  no  sign  of 
being  resolved  into  stars  by  an  instrument  of  four 
hundred  times  the  eye's  space-penetrating  power. 
Think  of  the  distance  expressed  by  four  hundred 
times  the  distance  of  the  milky  way  of  Androme- 
da —  five  millions  of  years,  as  flies  the  light ! 
Alas,  how  feeble  are  our  powers  !  How  they  la- 
bor and  bow  under  the  weight  of  such  mighty 
numbers  —  such  gates  of  Gaza  !  What  wondrous 
chronometers  those  must  be  which  could  take  fit- 
ting account  of  the  ongoings  of  such  far-off  firma- 
ments !  Could  you  stand,  with  a  wand  in  your 
hand  reaching  to  that  remotest  galaxy,  and  sweep 
it  around  you  in  every  direction,  what  an  empire 
fit  for  a  Jehovah  would  fall  within  the  embrace 
of  those  glorious  circles  !  And  yet  who  shall  say 
that  even  this  is  the  whole  astronomical  universe  ? 
What  right  have  we  to  stop  just  where  the  power 
of  our  instruments  happens  for  the  moment  to 
have  stopped,  and  say,  "This  is  the  end  —  these 
are  the  Pillars  of  Hercules  ?  Turn  back,  0  ad- 
venturous explorer  —  nothing  but  night  and  void 
in  this  direction  —  thou  hast  reached  the  last 
outpost  of  the  kingdom  of  the  Eternal !  Ne  plus 


150  FIFTH  LECTURE. 

ultra  !  "  No  :  thrice  no.  On  still  through  peo- 
pled infinitude,  through  raining  galaxies  and 
tornado-nebulae;  and,  while  thou  goest  outward 
still  through  the  charging,  storming  hosts  of  suns 
as  long  as  thought  can  fly,  or  angels  live,  say  ever 
to  thyself,  "  Lo,  these  are  parts  of  his  ways  ;  but 
how  little  a  portion  is  heard  of  him !  The  thunder 
of  His  power,  who  can  understand  ?  "  Is  not  space 
infinite  ?  Is  not  He  infinite  ?  And  who  dare 
say  that  his  works  are  not  wellnigh  infinite  too 
—  at  least  that  the  limit  to  which  our  gasping  and 
bewildered  astronomy  has  hitherto  conducted  us 
is  not,  as  it  were,  but  the  first  mile-stone  of  peo- 
pled space  ;  and  that  great  swarming  sphere  which 
our  mightiest  telescopes  have  gauged,  but  the 
merest  rain-drop  compared  with  another  swarming 
sphere  which  embraces  it  ?  But  let  us  suppose 
an  end ;  suppose  an  orbit  so  large  as  to  include 
in  its  unspeakable  round  the  entire  magnificence 
of  the  sidereal  heavens.  At  last  the  Ultima  Thule 
is  reached.  We  have  the  total  universe  of  matter 
which  God  has  made  —  one  all-comprehending  as- 
tronomical neighborhood — and  around  it  stretches 
in  all  directions  the  black  wastes  of  an  altogether 
endless  vacancy.  All  members  of  this  great  ulti- 
mate system  must  be  in  motion  about  its  common 
center  of  gravity.  Whether  this  sublime  center 
is,  or  is  not,  a  mathematical  point,  where  not  an 
atom  of  matter  nestles,  our  present  science  has  no 
means  of  determining.  But  is  there  not  some- 


UNIVERSE-SYSTEM.  151 

thing  at  the  bottom  of  our  hearts  better  than  sci- 
ence, which  invites  us  to  believe  that  what  would 
be  so  fitting  and  beautiful  is  also  triumphantly 
actual ;  namely,  that  at  the  center  of  this  august 
totality  of  revolving  orbs  and  firmaments  —  at 
once  the  center  of  gravity,  the  center  of  motion, 
and  the  center  of  government  to  all  —  is  that  better 
country,  even  the  heavenly,  where  reigns  in  glory 
everlasting  the  Supreme  Father  and  Emperor  of 
Nature  ;  the  capital  of  creation  ;  the  one  spot 
that  has  no  motion,  but  basks  in  majestic  and  per- 
fect repose  while  beholding  the  whole  ponder- 
ous materialism  which  it  ballasts  in  course  of  cir- 
culation about  it.  All  hail,  Central  Heaven  !  All 
hail,  innermost  Sun  Palace  and  celestial  Alham- 
bra !  All  hail,  believer's  Last  Home  —  from 
which  an  adult  astronomy,  fitted  with  the  pictured 
and  dynamical  wings  of  angels,  shall  immortally 
radiate  to  all  the  girdling  worlds  and  immortally 
bring  home  fresh  proofs  of  the  glory  of  Him  who 
has  so  long  been  defrauded  of  His  rights  among 
men  of  science  by  the  empty  names  of  law  and 
nature ! 


VI. 

AUTHOR    OF    NATURE, 

AS  RELATED  TO  ITS   LEADING  FEATURES. 

153 


VI.   AUTHOR  OF  NATURE, 

As  RELATED  TO  ITS   LEADING   FEATURES. 

1.  VASTNESS 159 

2.  VARIETY  IN  UNITY 163 

3.  FINISH  OF  MINIMA 168 

4.  WISDOM 171 

5.  DYNAMICS 177 

6.  RELATION  TO   LAW 182 

7.  RELATION  TO  TIME  AND   MOTION        .       .       .       .188 

8.  MYSTERY 193 


154 


SIXTH    LECTURE. 


AUTHOR  OF  NATURE. 

IS  there  an  Author  of  Nature  ?  Hitherto,  the 
affirmative  has  been  steadily  assumed  ;  and 
I  hope  that  at  this  point  such  a  question  seems 
almost  an  insult  to  your  understandings  —  freshly 
returned  as  they  are  from  sweeping  through  the 
unutterable  glories  of  the  astronomical  universe. 

Still,  let  the  preposterous  question  be  enter- 
tained. We  are  not  likely  to  realize  too  vividly 
the  existence  of  an  invisible  Divinity.  Though 
we  are  not  atheists  ;  though  we  would  be  shocked 
to  receive  that  dreary  and  awful  name  ;  though 
perhaps  it  has  never  once  occurred  to  us,  with 
our  Christian  training  and  surroundings,  to  doubt 
that  this  glorious  nature  about  us  has  the  God  of 
the  Scriptures  for  its  Father  and  King,  we  still 
belong  to  that  fallen  race  whose  strong  and  uni- 
versal tendency  is  to  be  without  God  in  the  world. 

Thcists  and  atheists  agree  as  to  the  advantage 
of  approaching  the  question  of  a  Divine  Being 

155 


156  SIXTH  LECTURE. 

with  a  mind  freshly  steeped  in  the  leading  facts 
and  courses  of  nature.  The  atheist  claims  that 
nature  makes  on  minds  thoroughly  imbued  with 
her  spirit  an  impression  adverse  to  faith ;  and 
points  in  evidence  to  some  eminent  cultivators 
of  the  physical  sciences  who  have  been  as  skep- 
tical as  they  have  been  scientific.  So  he  is  in 
favor  of  the  study  of  nature.  On  the  other  hand, 
the  theist  is  in  favor  of  it  for  the  very  oppo- 
site reason.  He  denies  the  atheism  of  science. 
He  refuses  to  infer  it  from  the  unbelief  of  some 
French  and  German  philosophers  —  with  here  and 
there  a  second-rate  English  disciple  —  whose 
minds  from  childhood  have  been  poisoned  with 
the  writings  of  Voltaire  and  his  school,  who  have 
seen  around  them  only  a  grotesquely  corrupted 
form  of  religion,  and  whose  private  lives  for  the 
most  part  were  such  as  to  make  it  greatly  for 
their  interest  to  have  no  God.  To  him  the  case 
of  such  exceptional  men  only  shows  the  exceed- 
ing force  of  native  depravity,  evil  training,  evil 
surroundings,  and  evil  habits,  at  withstanding 
the  natural  tendency  of  their  pursuits.  This 
tendency  he  regards .  as  strongly  theistic.  He 
thinks  he  sees  premonitions,  prophecies,  presump- 
tions, and  even  proofs  of  Divinity  in  the  great 
universe  that  expands  around  him ;  and  believes 
that,  other  things  being  equal,  the  more  fully 
one  comes  under  the  influence  of  the  astronomy, 
the  geology,  and  the  other  branches  of  natural 


AUTHOR   OF  NATURE.  157 

science  whose  findings  have  amazed  mankind, 
the  more  easily  he  will  admit  and  the  more 
strongly  he  will  hold,  the  doctrine  of  a  Divine 
Being. 

What  all  classes  think  it  well  to  do,  let  us  at- 
tempt. We  will  attempt  to  place  our  hearts  still 
more  fully  en  rapport  with  nature.  We  will,  if 
possible,  get  them  into  yet  closer  communication 
and  sympathy  with  its  great  leading  facts  and 
courses.  These  are  chiefly  astronomical.  Yet  I 
shall  not  restrict  myself  to  astronomical  facts, 
technically  so  called,  but  shall  allow  myself  to 
gather  from  the  whole  of  that  broad  field  of 
science  of  which  astronomy  is  the  undisputed 
and  all-comprehending  Chief.  And  I  can  not  but 
think  that  the  effect  will  be  to  preclude  objec- 
tions, to  furnish  presumptions,  and  generally  to 
dispose  the  mind  to  a  mighty  faith  in  God.  I 
am  persuaded  that  any  man  who  can  be  fairly 
set  down  in  the  midst  of  nature,  and  thrown 
honestly  open  to  all  its  subtle  inductions,  mag- 
netisms, inspirations,  will  silently  drink  in  theism, 
as  a  fleece  spread  out  under  the  stars  drinks  in 
the  dew. 

Suppose  it  claimed  that  a  certain  veiled  paint- 
ing is  the  work  of  Titian.  If,  on  gradually  lifting 
the  veil,  we  find  exclusively  trait  after  trait  such 
as  might  have  been  expected  in  a  work  by  that 
great  master,  our  disposition  to  think  favorably  of 
the  claim  increases  with  every  step :  and  if,  when. 


158  SIXTH  LECTURE. 

the  canvas  is  entirely  exposed,  every  leading  fea- 
ture seems  Titianic  and  the  whole  worthy  of 
such  an  author,  our  minds  are  far  advanced 
toward  faith  —  they  are  in  a  state  of  high  prep- 
aration for  any  ulterior  evidence,  and  only  com- 
paratively little  of  it  will  be  required  to  secure 
full  conviction.  And  this  is  reasonable.  Pre- 
vious to  examination,  how  could  we  be  sure  that 
there  were  not  lurking  under  that  veil  incompat- 
ibilities, or  at  least  disagreements  ?  Now  our 
uncertainty  is  removed.  We  have  found  positive 
harmonies.  The  facts  match  the  claim.  The 
picture  is  such  as  might  have  been  expected  from 
Titian  —  such  indeed  as  he  would  surely  have 
painted.  His  great  characteristics  are  strikingly 
here.  And  these  are  so  many  verisimilitudes,  so 
many  presumptions  in  favor  of  the  claim  :  and,  in 
the  absence  of  all  evidence  to  the  contrary,  at 
least  authorize  the  critic  to  stand  at  the  very 
verge  of  assent,  facing  it  kindly  and  with  foot 
uplifted,  ready  to  cross  the  border  at  the  first 
competent  invitation.  Let  such  an  invitation 
come  in  the  shape  of  an  assurance  that  the  paint- 
ing is  almost  universally  accepted  as  the  work  of 
Titian,  especially  among  the  most  intelligent  and 
fair-minded  judges;  further,  that  the  hypothesis 
which  ascribes  the  work  to  him  is,  as  compared 
with  other  hypotheses,  altogether  the  simplest, 
the  least  embarrassed,  the  most  useful,  as  well  as 
the  most  historical  —  this  would  and  should  plant 
liis  feet  in  the  very  center  of  faith. 


VASTNESS  OF  NATURE.  159 

Now  it  is  claimed  that  nature  is  the  work  of 
God.  Let  us,  step  by  step,  unveil  its  leading- 
features  and  see  if  they  do  not  strikingly  harmo- 
nize with  the  claim:  and,  as  they  may  be  found 
to  do  so,  let  unbelief  approach  its  frontier ;  and, 
when  at  last  the  general  scheme  of  nature  appears 
characteristic  and  worthy  of  God,  let  the  traveler 
at  least  stand  on  the  last  boundary  of  his  chill 
and  somber  territory,  all  ready  to  cross  with  de- 
cisive and  ringing  step  into  a  brighter  land  at 
the  first  summons  of  the  positive  evidence. 

What  I  propose,  then,  in  the  present  lecture,  is 
to  illustrate  the  general  harmony  between  nature 
and  the  doctrine  of  a  God.  Of  course,  a  few 
specimen  illustrations  are  all  that  can  be  offered. 
One  will  do  well  to  feel  the  pulse  of  nature  still 
more  fully  in  the  works  of  Ray  and  Good  and 
Paley,  in  the  Bridgewater  Treatises,  and  in  later 
works  of  the  same  character. 

One  of  the  most  striking  features  of  what  we 
call  Nature  is  its  vastness. 

I  do  not  forget  that  I  am  speaking  to  those  who 
have  become  familiar  with  the  wonders  of  physical 
science.  But  neither  do  I  forget  that  even  the 
scholar  must  refresh  his  impressions  of  things  in 
very  much  the  same  way  with  other  men.  So  I  ask 
you  to  think  of  plains  stretching  to  the  horizon  ; 
of  mountains  piercing  the  clouds ;  of  roomy  con- 
tinents anchored  in  roomier  oceans';  of  this  whole 
earth-sphere,  with  its  huge  baldric  of  twenty-five 


100  SIXTH  LECTURE. 

thousand  miles,  covered  with  innumerable  ve- 
getable products,  peopled  with  men  to  the  poten- 
tial figure  of  a  thousand  millions,  swarming  still 
more  potentially  with  the  lower  animals,  and  so 
flooded  with  microscopic  life  that  almost  every 
cubic  inch  of  air  and  water  and  soil  is  panting 
with  an  incalculable  population,  —  some  of  whose 
smaller  individuals  multiply  themselves  into 
one  hundred  and  seventy  billions  in  four  days  ; 
gather  their  five  hundred  millions  in  a  single 
drop  of  water ;  and  yet  make  up,  with  the  stony 
cerements  of  the  merest  fraction  of  their  fossil 
ancestry,  whole  mountains  and  geologic  beds. 
Such  is  our  world.  Out  in  yonder  vault,  find 
that  millionfold  world  which  we  call  the  sun, 
with  its  invisible  retinue  of  a  hundred  earths  • 
out  in  yonder  vault,  when  night  falls,  find  a 
thousand  suns  similarly  attended ;  with  tube 
Galilean,  thousands  more;  with  tube  Herschel- 
ian,  millions  more ;  with  tube  Rossian,  billions 
more.  Is  this  the  end  ?  What  astronomer  for 
one  moment  imagines  that  another  enlargement 
of  the  great  speculum  at  Parsonstown  would 
show  our  vision  to  be  already  hard  up  against 
the  frontiers  of  nature  ?  Not  even  Darwin  doubts 
that  successive  improvements  in  the  space-pene- 
trating power  of  our  instruments  would  go  on 
indefinitely  opening  up  firmaments  at  every  step. 
Where  is  the  verge  of  the  universe  ?  Who  would 
undertake  the  roll-call  of  its  orbs  ?  Who  dares 


OF  NATURE.  161 


to  say  that  he  could  count  through  the  grand 
total  of  its  firmaments,  even  though  he  should 
count  a  thousand  years  ?  Figures  go  but  a  small 
way  toward  expressing  the  dimensions  of  such  a 
universe  —  whether  one  considers  the  number  of 
its  worlds,  or  the  expanse  of  space  through  which 
they  are  distributed.  Our  world  spins  round  its 
ellipse,  of  well-nigh  two  hundred  million  axis, 
without  ever  having  a  neighbor  nearer  than 
thirty  millions  of  miles,  save  its  own  moon. 
The  interval  between  our  sun  and  the  nearest 
star  of  the  same  galactic  nebula  is  twelve  hun- 
dred thousand  times  this  distance.  And  then 
the  distance  from  nebula  to  nebula  —  it  is  abso- 
lutely awful.  Our  telescopes  sweep  a  sphere  of 
stars  whose  diameter  is  seven  millions  of  years,  as 
light  travels.  Calculation  covers  its  abashed  face 
with  its  great  wings  in  the  presence  of  these  over- 
whelming amplitudes.  And  such  is  nature  ! 

Certainly  such  a  universe  as  this  does  not  cry 
out  against  the  existence  of  a  God  whose  essen- 
tial attribute  is  immensity.  On  the  contrary,  it 
is  just  such  a  universe  as  one  would  have  ex- 
pected to  come  from  such  a  being.  Nay,  given  a 
Deity  who  is  practically  at  home  in  every  point 
of  space,  whose  attributes  are  laid  out  on  a  scale 
of  unbounded  vastness,  to  whom  it  is  just  as  easy 
to  make  and  govern  a  trillion  of  worlds  as  it  is  a 
grain  of  sand,  and  the  imperial  fitness  of  things 

would  demand  that  li  e  people  vacancy  with  very 
11 


162  SIXTH  LECTURE. 

much  that  profusion  and  breadth  of  being  that 
we  actually  see.  The  work  ought  to  express  and 
honor  the  workman.  And  when  I  am  told  of  an 
author  of  nature  who  is  immense  with  a  three- 
fold boundlessness  of  intelligence,  might,  and 
years ;  so  that  to  him  our  great  and  small,  our 
far  and  near,  our  center  and  circumference  — 
though  that  circumference  sweep  around  all  the 
expanses  of  modern  astronomy  —  are  practically 
the  same  ;  so  that  he  can  properly  challenge,  "Do 
not  I  fill  heaven  and  earth  ?  "  —  when  I  am  told 
of  this,  and  I  then  place  myself  out  under  the 
open  dome  of  nature,  amid  its  exuberant  objects 
and  marvelous  stretches,  I  feel  myself  silently 
drinking  in  predispositions  to  faith  as  the  fleece 
spread  out  under  the  open  heaven  drinks  in  the 
dew.  I  feel  that  the  doctrine  matches  facts  ;  that 
the  theory  has  in  its  favor  a  comprehensive  veri- 
similitude and  presumption  ;  that  Nature,  instead 
of  saying,  "  There  is  no  immense  God,"  signifi- 
cantly asks,  in  a  tone  of  encouragement  and  with 
a  look  of  incipient  expectation,  "Is  there  not  such 
a  Being?  "  In  fine,  I  feel  that  our  slight  lifting 
of  the  veil  from  the  painting  has  disclosed  a  fea- 
ture strikingly  characteristic  of  the  great  master 
to  whom  the  work  is  attributed  —  a  feature  which, 
in  the  absence  of  all  counter-evidence,  naturally 
sets  our  faces  faithward  —  one,  of  several  har- 
monies which,  as  successively  presented,  will  war- 
rant us  in  looking  faithward  with  evergrowing 
kindliness  of  aspect. 


VARIETY  IN  UNITY.  163 

Notice  with  me  the  variety  in  unity  that  char- 
acterizes Nature. 

Some  hundreds  of  millions  of  creatures  on  our 
earth  are  so  much  alike  that  we  put  them  into  a 
class  by  themselves  and  call  them  men.  They  are 
all  alike  in  certain  fundamental  features ;  and  yet 
each  man  differs  materially,  both  in  body  and  soul, 
from  every  other  man.  So  of  every  other  class 
of  things  —  animal,  vegetable,  inorganic;  while 
there  is  a  sub-s,tratum  of  unity  among  the  mem- 
bers of  each,  on  account  of  which  they  are 
classed  together,  there  is  not  one  which  is  not 
very  unlike,  in  many  respects,  all  its  fellows.  All 
animals  have  great  points  in  common  :  but  how 
many,  many  sorts  of  animals  ;  and  how  great  the 
difference  between  the  eagle  and  the  microscopic 
mote,  between  the  cetus  and  the  polyp,  between 
the  most  perfect  man  (body  and  soul)  and  the 
rudest  of  the  polypi !  All  vegetables  are  similar- 
ly constituted  :  but  whose  memory  can  master  all 
the  distinct  kinds  of  vegetables  in  the  wide  intei>- 
val  between  the  spire  of  grass  and  the  huge  tree 
that  wrestles  victoriously  with  stormy  centuries  ; 
and  reckon  up  the  great  differences  that  exist,  as 
to  shape  and  size  and  color  and  flavor  and  odor, 
among  fruits  and  flowers  and  leaves  and  grasses 
and  shrubs  and  trees.  Great  threads  of  unity 
obviously  connect  all  the  forms  of  terrestrial 
being,  organic  and  inorganic ;  but  this  we  know, 
that,  if  only  single  specimens  of  all  the  plainly 


164  SIXTH  LECTURE. 

separated  species  were  attempted  to  be  brought 
together  into  one  Crystal  Palace  of  a  museum,  we 
should  have  to  roof  in  empires,  instead  of  acres, 
in  order  to  accommodate  their  mighty  array:  and  as 
our  eye  would  run  over  the  whole  superb  collec- 
tion, and  at  last  bring  together  the  two  termini — • 
viz.,  the  material  man  and  the  material  stone 
just  crumbling  into  dust  —  our  sense  would  be 
that  of  a  miraculous  diversity  efflorescing  out  of 
the  unity  of  our  world.  So  with  those  other 
worlds  that  shine  or  hide  in  the  vault  above. 
They  are  all  spheres,  all  have  orbitual  and  prob- 
ably axial  motions,  all  are  governed  by  the  same 
principle  and  law  of  gravitation,  all  are  lighted 
and  colored  and  warmed  by  the  same  mysterious 
element  or  impulse  ;  but  on  such  basal  unity  is 
superimposed  an  almost  infinite  variety.  Observe 
our  solar  system.  One  member  of  it  is  self-lu- 
minous, and,  relatively  to  the  other  members,  a 
nearly  stationary  body  ;  the  others  are  dark,  and 
far-wandering  planets.  One  is  one  hundred  miles 
in  diameter,  another  nearly  one  hundred  thou- 
sand, while  still  another  contains  more  than 
eight  hundred  times  as  much  matter  as  all  the 
remainder  of  the  system  can  boast.  Some  have 
atmospheres  and  seas,  others  have  neither.  Some 
have  moons,  others  have  none.  Saturn  rides 
forth  in  the  porip  of  three  great  equatorial  rings, 
as  well  as  of  eight  moons  ;  no  other  planet  is  simi- 
larly furnished.  These  orbs  of  our  system  differ 


VARIETY  IN  VNITY.  165 

greatly  in  density  —  one  is  as  lead,  another  as 
cork,  another  still  is  mere  vapor.  One  receives 
seven  times  as  much  light  from  the  sun  as 
we,  another  only  a  three  hundred  and  sixtieth 
part  of  as  much.  Neptune's  year  is  equal  to 
one  hundred  and  sixty-five  of  our  years.  Saturn's 
day  is  only  one-half  of  our  day.  Of  course 
the  products  and  scenery  of  these  worlds,  as 
well  as  the  constitution  of  their  inhabitants, 
must  differ  exceedingly.  But  pass  we  on  to 
the  region  of  the  fixed  stars.  Have  we  es- 
caped into  immeasurable  uniformity  out  of  im- 
measurable variety  ?  Lo  !  we  skirt  systems,  clus- 
ters, firmaments,  and  never  two  alike,  while  some 
stand  apart  by  whole  universes  of  difference ! 
Lo,  systems  with  several  suns  each,  from  one  to  a 
hundred  !  Lo,  systems  lighted,  some  with  white 
suns,  some  with  ruby,  some  with  emerald,  and 
some  with  suns  of  many  different  colors  !  Lo, 
suns  differing  exceedingly  in  size  and  amount  of 
light  they  shed :  for  the  great  Sirius  that  flashes 
first  magnitudes  on  all  our  charts  as  well  as  on 
the  dazzled  retina  of  the  savage,  is  not  as  near 
to  us  as  the  little  61  Cygni,  and  its  light  must 
be  equal  to  that  of  two  hundred  and  fifty  suns 
like  our  own  !  Alcyone  shines  with  a  force 
of  twelve  thousand  suns.  And  then  :ve  have 
suns  themselves  combined  into  systems  of  all 
sizes  and  shapes  —  systems  of  two,  of  three, 
of  many,  of  millions,  —  firmaments  which,  un- 


166  SIXTH  LECTURE. 

der  the  name  of  nebulae,  are  the  last  gen- 
eralization and  most  stupendous  variety  of  mod- 
ern discovery  :  sometimes  rolled  up  into  spheres  : 
sometimes  gathered  into  circular  or  elliptic  rings; 
now  fan-shaped  ;  now  like  an  hour-glass  ;  now 
broad  wheels  of  compacted  suns,  large,  glitter- 
ing, and  sublime  enough  to  under-roll  the  chariot 
of  immeasurable  God.  There  are  not  two  leaves 
or  grass-blades  perfectly  alike  in  all  this  verdant 
world  ;  not  two  worlds,  nor  systems  of  worlds, 
accurately  alike  in  all  the  prodigious  realms  of 
astronomy. 

Now  no  one,  to  say  the  least,  can  claim  that  this 
vast  variety  imbosomed  in  unity  makes  positively 
against  the  idea  of  one  Creator  of  boundless  in- 
vention and  executive  faculty.  On  the  contrary, 
it  is  just  what  we  should  have  expected  from  such 
a  being.  Given  just  such  a  many-sided,  versatile, 
complete  Deity  as  is  affirmed  —  we  should  say 
that,  in  case  he  should  set  himself  to  produce  a 
vast  universe,  he  would  be  likely  to  produce  one 
in  which  great  outlines  of  unity  would  be  steeped 
in  immeasurable  variation  ;  one  in  which  resem- 
blance and  diversity,  both  robed  and  featured  like 
goddesses,  would  hold  each  other  by  the  hand 
and  go  treading  with  wedded  and  festival  step  up 
and  down  the  whole  quickened  area.  Nay,  this 
sort  of  universe  one  wouH  make  sure  of  finding ; 
would  be  greatly  disappo'nted  if  he  should  not 
find.  The  eternal  laws  ol  his  own  nature  would 


VARIETY  IN  UNITY.  167 

demand  it  of  the  Great  Builder.  The  invin- 
cible beauty  and  fitness  of  things  would  de- 
mand it.  Perfect  uniformity,  however  piled  up 
in  magnificent  magnitudes  —  even  a  uniformity 
only  varied  after  so  cramped  and  frugal  a  fashion 
as  would  be  perpetually  suggesting  poverty  of  re- 
sources —  would  belie  the  inexhaustible  Divinity. 
If  he  build  at  all,  he  must  not  misrepresent  and 
disparage  himself  in  his  work  ;  his  fruitful  na- 
ture, teeming  with  all  imaginable  fertilities  and 
seeds,  must  surely  blossom  into  very  much  that 
marvelous  fruitfulness  of  product  and  pattern 
which  we  observe.  And  when  I  am  told  of  an 
author  of  nature  whose  being  swarms  in  resistless 
force  toward  every  point  of  the  compass,  nay  of  the 
sphere ;  who  is  both  a  unit  and  a  polygon,  facing 
every  desideratum  and  possibility  with  a  flashing 
side,  both  of  thought  and  action,  that  out-dazzles 
the  sun  —  when  I  am  told  that  such  a  being  is 
the  author  of  nature,  and  I  then  put  myself 
forth  under  the  open  dome  amid  the  glorious  di- 
versities that  root  themselves  in  the  *  glorious 
unity  of  nature,  and  open  myself  freely  to  all 
their  subtle  suggestions  and  magnetisms,  I  feel 
myself  drinking  in  predispositions  to  faith,  as  the 
exposed  fleece  drinks  in  the  dew.  I  feel  that 
again  the  doctrine  matches  facts,  that  again  the 
theory  has  a  comprehensive  verisimilitude  and  pre- 
sumption, that  Nature  instead  of  saying  that 
there  is  no  God  whore  unity  is  arborescent 


1C8  SIXTH  LECTURE. 

with  endless  varieties  of  beauty  and  power,  sig- 
nificantly asks,  "Is  there  not  such  a  Being?  In 
fine,  I  feel  that  our  continued  lifting  of  the  veil 
from  the  painting  has  disclosed  a  second  trait 
strikingly  characteristic  of  the  Great  Master  to 
whom  the  work  is  attributed  ;  a  trait  which,  added 
to  the  first,  warrants  our  faith  ward  look  in  taking 
on  new  kindliness  of  aspect. 

Another  characteristic  of  nature  deserving  of 
notice  is  the  perfection  of  its  details. 

The  exquisite  finish  of  nature  in  its  minutest 
parts  is  about  as  wonderful  as  its  vastness  and  va- 
riety. Scan  that  leaf.  Examine  the  wing  of  that 
butterfly.  Let  the  tinted  and  polished  antennas 
of  that  moth  glitter  in  the  focus  of  your  instru- 
ment. Subject  to  the  skilfullest  notice  of  science 
and  art  the  smallest  veins  of  any  animal  or  vege- 
table. Push  the  analysis  just  as  far  as  possible, 
and  submit  that  last  visible  minimum  of  organi- 
zation in  the  crystalline  lens  of  the  cod,  with  its  five 
millions  of  muscles  and  sixty  thousand  millions 
of  teeth,  to  the  most  searching  criticism  of  the  su- 
perbest  microscope.  What  exquisite  details  1 
What  elaborate  refinement  of  workmanship  !  It 
Is  not  as  with  some  master-piece  of  human  paint- 
ing —  the  main  points  only  cared  for,  while  all 
the  subordinate  are  too  rude  to  bear  close  inspec- 
tion. Titian  painted  this  landscape.  Well,  it  is 
worthy  of  him  —  the  general  effect  is  beautiful. 
Yet,  if  you  approach,  and  closely  examine  the  fo- 


FINISH  OF  MINIMA.  169 

liage  of  the  trees,  the  grass  with  which  the  can- 
vas is  green,  or  even  the  limbs  and  features  of 
the  animals,  they  will  be  found  very  coarsely  and 
incorrectly  executed.  The  microscope  turns  the 
most  finished  work  of  man  into  coarseness  and 
clumsiness  —  indeed,  almost  immediately  carries 
the  sight  where  traces  of  skill  have  totally  disap- 
peared. Not  so  with  the  works  of  nature.  A 
real  landscape  you  may  analyze  to  your  heart's 
content,  and  inspect  its  details  as  critically  as 
eye  armored  with  lens  can  do,  without  finding 
the  workmanship  growing  less  exquisite  the  fur- 
ther you  push  inquiry.  A  real  man  —  you  may 
descend  to  the  minutest  particulars  of  his  organi- 
zation, and  get  as  near  its  primary  elements  as 
an  Ehrenberg  with  his  superb  instruments  and 
practiced  vision  can  carry  you,  without  finding 
the  least  falling  off  from  that  delicacy  of  execu- 
tion which  appears  on  the  larger  masses  and  out- 
lines of  the  body.  So  everywhere  among  natural 
objects  —  the  great  and  the  small,  the  outlines 
and  the  minute  filling-up,  as  far  as  utmost  optical 
resources  can  carry  our  observation,  are  wrought 
with  apparently  the  same  overflowing  outlay  of 
attention  and  skill.  It  is  not  so  in  a  few  instances 
merely,  nor  in  a  thousand — it  is  so  universally. 

That  there  are  any  so  preposterous  as  to  think 
that  this  feature  of  nature  makes  positively 
against  the  idea  of  a  sparrow- watching,  hair-num- 
bering, and  thought-weighing  God  is,  of  course, 


170  SIXTff  LECTURE. 

not  to  be  imagined.  Of  course,  it  is  a  feature 
that  fully  harmonizes  with  such  an  idea.  A  na- 
ture finished  exquisitely  down  to  the  most  infinites- 
imal of  its  details  is  just  what  one  would  have 
predicted  from  a  God  of  this  description.  An- 
nounced the  fact  that  He  was  about  to  create, 
and  expectation  would  have  stood  on  tiptoe  to  look 
for  just  such  a  nature  as  we  see.  A  God  for  whose 
vision  nothing  is  too  small,  who  necessarily  gives 
as  complete  attention  to  the  affairs  of  an  atom  as 
to  those  of  an  empire,  who  can  concentrate  his 
almightiness  with  as  much  freedom  and  accuracy 
on  a  mathematical  point  as  on  a  world,  who  is 
embarrassed  no  more  by  unlimited  multiplicity 
than  by  unlimited  minuteness  of  details,  who  can 
with  equal  ease  paint  a  landscape  on  the  point  of 
a  needle  —  say,  if  you  please,  forty  thousand  of 
such  landscapes  at  once,  with  all  their  innumera- 
ble and  minima  particulars,  back  of  the  reticu- 
lated eyes  of  a  single  butterfly  —  can  with  equal 
ease  do  this,  and  roll  a  solar  system  on  its  tri- 
umphant path  about  the  Pleiades  ;  do  I  not  know 
that  a  being  with  such  a  striking  attribute  as  this 
would  surely  give  it  expression  in  his  works  ?  Do 
I  not  know  that  he  who  is  equally  at  home  in 
maxima  and  minima,  and  to  whom  beauties  and 
glories  in  the  world  of  infinitesimals  would  be  just 
as  apparent  and  practicable  as  they  are  in  the 
world  of  infinites,  would  lay  himself  out  on  the 
one  very  much  as  on  the  other  —  would  effulge 


WISDOM  OF  NATURE.  171 

himself  into  the  microcosmos  very  much  as  into 
the  cosmos  :  When,  then,  I  am  told  that  such  a 
being  is  the  author  of  nature,  and  I  proceed  to 
place  myself  out  under  the  open  dome  amid  the 
exquisite  elaborations  that  swarm  on  every  hand 
down  through  the  veriest  miracles  of  littleness 
and  detail,  and  to  uncover  myself  candidly  to  all 
their  subtle  whisperings  and  magnetisms,  I  feel 
myself  softly  drinking  in  predispositions  to  faith, 
as  the  exposed  fleece  drinks  in  the  dew,  I  so  feel 
the  force  of  a  doctrine  matching  facts,  and  but- 
tressing itself  again  and  again  with  comprehen- 
sive verisimilitudes  and  presumptions,  that  to 
me  nature  becomes  articulate,  and,  instead  of 
swearing  with  uplifted  hand  that  there  is  no 
wondrous  God,  significantly  points  upward,  and, 
with  bated  breath  and  expectant  look,  asks,  "  Is 
there  not  such  a  Being?"  —  in  fine,  I  feel  that 
our  continued  lifting  of  the  veil  from  the  paint- 
ing has  disclosed  another  characteristic  of  the 
Great  Master  to  whom  the  work  is  attributed,  the 
third  of  those  several  harmonies  which,  as  suc- 
cessively presented,  warrant  us  in  looking  faith- 
ward  with  ever-growing  kindliness  of  aspect. 

Another  feature  of  Nature  is  what  I  shall  call 
its  wisdom. 

The  world  is  full  of  what,  if  accepted  as  the 
work  of  an  intelligent  being,  would  be  called  con- 
trivances—  adaptations  of  means  to  ends  — often 
of  the  most  complex  and  elaborate  description. 


172  SIXTH  LECTURE. 

For  example,  the  birds  —  how  admirably  adapted 
to  flying  ;  in  shape,  feathers,  bones,  wings  !  The 
fishes  —  how  adapted  to  swimming  and  life  in  the 
water ;  witness  their  shape,  their  smooth  and 
unctuous  scales,  their  pairs  of  fins,  their  tails  and 
gills  !  The  land-animals  —  how  adapted  to  walk- 
ing and  running  and  feeding  on  the  earth's  sur- 
face ;  to  eat  the  grass  or  catch  their  special  prey  ! 
The  trees  —  how  adapted  to  stand  firmly  ;  by  their 
roots,  their  perpendicularity,  their  balanced 
branches,  their  moderate  flexibility  — how  adapt- 
ed for  shade,  for  abating  the  violence  of  winds, 
for  fuel !  Or,  if  you  will  consider  particular  or- 
gans of  the  organic  tribes,  look  at  the  bark  of 
trees  as  related  to  their  nourishment,  at  the  web- 
foot  in  its  double  relation  to  land  and  water,  at 
the  teeth  and  other  preparers  of  food  for  the 
stomach,  at  the  stomach  as  a  preparer  of  food  for 
the  blood,  at  the  lungs  as  purifiers  of  the  blood, 
at  the  heart  as  the  engine  for  forcing  the  blood  to 
all  parts  of  the  system,  at  the  hand  as  the  general 
servant  of  the  whole  body  ;  in  short,  at  almost  any 
organ  of  either  animal  or  vegetable  structures. 
The  adaptations  are  wonderful.  They  are  physi- 
cal miracles  —  the  means  are  shaped  and  applied 
to  the  ends  so  exactly,  beautifully,  triumphantly. 
For  example,  no  work  of  human  ingenuity  that 
ever  you  saw  is  equal  to  that  natural  marvel,  the 
human  eye  —  an  organ  having  reference  to  an 
element  quite  external  to  itself,  whose  chief  source 


WISDOM  OF  NATURE.  173 

is  millions  of  leagues  distant ;  and  also  to  millions 
of  external  objects  which  compose  our  scenery  of 
earth  and  sky  —  an  organ  placed  in  the  most  ele- 
vated part  of  the  body  so  as  to  command  the  most 
extensive  prospect ;  placed  in  the  front  so  as  most 
readily  to  preside  over  the  direction  in  which  we 
habitually  move  ;  placed  in  a  strong  bony  socket 
which  defends  it  from  the  heavier  external  in- 
juries ;  imbedded  in  a  soft  cushion,  so  that  its  del- 
icate texture  can  not  be  hurt  by  the  bony  walls 
around  it,  as  it  rests  on  them,  and  turns  swiftly 
hither  and  thither  at  the  bidding  of  the  will ; 
furnished  with  lids,  like  curtains,  to  close  over  it 
in  sleep,  to  wipe  it,  to  cut  off  the  outer  rays  of 
light  that  would  confuse  vision,  to  protect  it  by 
their  involuntary  and  instantaneous  shutting 
against  the  lighter  kind  of  injuries  ;  furnished 
with  an  apparatus  of  muscles  by  which  it  can  be 
rapidly  turned  at  choice  in  any  direction,  so  as  to 
vary  the  field  of  vision  as  the  needs  of  life  may 
suggest ;  furnished  with  a  self-acting  system  of 
appliances  by  which  the  ball  is  kept  lubricated  for 
easy  movement;  furnished  with  a  conduit  to 
carry  off  the  superfluous  moisture ;  furnished 
with  just  that  shape,  out  of  ten  thousand  possible 
shapes,  which  mathematicians  have  demonstrated 
to  be  the  only  one  which  can  refract  all  the  rays 
of  light  to  a  single  surface,  and  thus  afford  dis- 
1/;ict  vision,  viz.,  that  of  an  ellipsoid  of  revolu- 
tion ;  furnished  with  a  retina  or  natural  canvas 


174  SIXTH  LECTURE. 

on  which  its  pictures  of  external  objects  can  be 
formed,  of  just  the  right  size,  and  at  just  the  right 
distance  behind  the  lenses  of  the  eye ;  furnished 
with  lenses  of  different  substances  having  differ- 
ent refractive  powers,  thereby  preventing  the  light 
from  being  resolved  into  the  prismatic  colors,  and 
thus  misrepresenting  and  uniforming  objects  ;  fur- 
nished in  front  with  a  perforated  membrane  that 
by  self-adjustment  adapts  it  to  different  degrees 
of  light,  also  with  a  system  of  pulleys  and  liga- 
ments that  at  a  moment's  warning  alter  its  con- 
vexity and  the  relative  position  of  parts  so  as 
to  adapt  it  to  objects  at  different  distances  and, 
what  is  more  wonderful  than  all,  provided  in 
some  inscrutable  manner  with  the  means  of  ex- 
pressing the  mind  itself,  so  that  one  may  look  into 
its  crystal  depths  and  see  intellectuality  and  scorn 
and  wrath  and  love,  and  almost  every  spiritual 
state  and  action.  Now,  if  this  is  not  an  amazing 
congeries  of  adaptations,  there  is  and  can  be  noth- 
ing amazing.  If  found  to  be  the  work  of  a  human 
artist,  it  would  be  called  a  perfect  marvel  of  in- 
genuity and  wisdom.  And  yet  some  insects  have 
twenty  thousand  such  eyes  combined  into  one. 
But  the  eye  is  only  one  among  an  infinity  of 
natural  contrivances.  Animate  and  inanimate 
nature  is  mountainous  and  glittering  with  them. 
Down  into  the  regions  of  the  infinitely  small, 
whither  only  the  most  searching  microscopes  car- 
ry the  sight ;  up  into  the  regions  of  the  infinitely 


WISDOM  OF  NATURE.  175 

large  and  far,  whither  only  mightiest  telescopes 
lift  our  struggling  knowledge ;  among  the  mech- 
anisms of  the  atomic  nations  that  people  a  sin- 
gle leaf,  and  among  the  mechanisms  of  those 
swarming  celestial  empires  whose  starry  banners 
sweep  our  nightly  skies  —  it  is  everywhere  the 
same  ;  exquisite  adaptations  crowding  exquisite 
adaptations,  profound  contrivances  (so  inven- 
tors and  mechanicians  would  be  tempted  to  call 
them)  heaped  on  profound  contrivances,  in  such 
endless  amounts  and  varieties  of  wise  structure, 
as  exhausts  all  human  understanding  and  dwarfs 
into  nothingness  all  the  products  of  human  in- 
genuity. 

Does  such  a  nature  as  this  swear  against  a 
Divine  Contriver.  Does  it  protest  against  him,  or 
testify  against  him,  or  breathe  even  a  suspicion 
against  him  ?  Many  absurd  things  are  done  in  the 
world  :  but  it  will  be  hard  to  find  the  man  who  will 
care  to  deny  the  positive  and  emphatic  harmony 
between  the  doctrine  of  an  omniscient  and  omnip- 
otent God  and  a  universe  crowded  with  such 
splendors  of  natural  mechanics.  A  God  of  end- 
less invention,  and  whose  powerful  and  skilled 
hands  can  magnificently  realize  all  that  he  has 
magnificently  planned  —  we  should  expect  that 
such  a  being,  in  case  he  should  create  a  nature, 
would  set  it  all  ablaze  with  the  monuments  of 
his  supreme  intelligence  and  power  —  should  be 
disappointed  to  find  no  such  monuments,  but,  in 


176  SIXTH  LECTURE. 

their  stead,  mere  stupidity  or  tameness  of  work. 
We  should  call  the  work  unworthy  of  the  work- 
man. Nay,  we  should  hasten  to  say  to  ourselves 
that  we  must  have  mistaken  him  —  He  could 
really  be  nothing  more  than  such  a  petty  divinity 
as  the  poor  heathen  have  fabled  to  themselves. 
For  we  should  be  sure  that  one  having  unlimited 
command  of  ways  and  means,  both  as  a  knower 
and  worker,  would  display  it  in  his  works.  It 
being  just  as  easy  for  him  to  have  exquisite 
adaptations,  and  a  gloriously  endless  variety  of 
them,  as  to  have  no  adaptations  at  all  —  it  is 
plain,  what  sort  of  nature  he  ought  to  make  and 
would  make.  Now  let  me  be  told  of  a  framer  of 
nature  in  whom  are  hid  all  the  treasures  of  wis- 
dom and  knowledge,  whose  light  has  in  it  no  dark- 
ness at  all,  whose  smallest  deeds  have  from  the 
hoary  everlasting  been  pavilioned  and  charioted 
toward  being  amid  the  glories  of  Almighty  Om- 
niscience ;  and  I  then  place  myself  out  under 
the  open  dome  mid  the  wilderness  of  wonderful 
constructions  and  chemistries,  and  candidly  un- 
cover myself  to  all  their  subtle  sympathies  and 
magnetisms  —  I  feel  myself,  all  silently,  drinking 
in  predispositions  to  faith,  as  the  exposed  fleece 
drinks  in  the  dew.  I  feel  that  the  God  who  is  af- 
firmed is  just  the  God  to  match  the  nature  which 
I  see  —  here  the  ball  and  there  the  socket,  here 
the  foot  Titanic  and  there  its  footprint,  here  the 
shapely  hand  and  there  its  glove,  here  the  sover- 


POWER    OF  NATURE.  177 

eign  sword  and  there  the  golden  scabbard  that  just 
fits  it  —  that  these  noble  adaptations  and  mechan- 
isms, spangling  and  blazoning  all  the  fields  of 
matter,  are  in  rejoicing  sympathy  with  the  idea 
of  a  Creator  who  is  wonderful  in  counsel  and  ex- 
cellent in  working ;  that  the  alabaster-box  of 
precious  wisdom  that  has  been  emptied,  not  only 
on  the  queenly  head  and  shining  tresses  of  Na- 
ture but  on  her  very  feet,  scents  bravely  of  One 
who  is  himself  a  "  mountain  of  such  spikenard  ;" 
that,  in  fact,  the  theory  is  again  smiled  upon 
by  a  comprehensive  verisimilitude  and  presump- 
tion ;  that  Nature,  instead  of  swearing  with 
uplifted  hand  that  there  is  no  All-wise  Creator, 
with  flushed  cheek  and  upward-glancing  eye  of 
expectation,  significantly  asks,  "  Is  there  not  such 
a  Being  ?  "  In  fine,  I  feel  that  our  continued 
lifting  of  the  veil  from  the  painting  has  disclosed 
still  another  characteristic  of  the  Great  Master 
to  whom  the  work  is  attributed  ;  has  cleared  up 
another  stretch  of  that  vista  at  the  end  of  which 
is  Titian  at  his  easel  —  the  fourth  of  those  several 
harmonies,  which,  as  successively  presented,  war- 
rant us  in  looking  faithward  with  ever-growing 
kindliness  of  aspect. 

Another  striking  feature  of  Nature  is  its  power. 

No  contemptible  degree  of  force  resides  in  the 

muscles  of  some  men  —  the  Samsons  and  Milos 

of  their  time.     Huge  rocks  are  lifted,  tough  oaks 

are  riven,  great  structures  are  shaken  down  by 

12 


178  SIXTH  LECTURE. 

their  hands.  Many  brute  animals  display  still 
greater  muscular  strength  ;  witness  the  elephant, 
and  those  gigantic  mammals  which  towered 
and  ruled  over  the  post-tertiary  savannas.  A 
combination  of  animal  forces  with  what  are  called 
the  mechanical  powers  often  generates  measures 
of  force  more  striking  still ;  and  when  men  stand 
by  such  piles  as  the  Egyptian  pyramids,  they  are 
deeply  impressed  with  the  prodigious  uplift  that 
must  have  put  those  mighty  blocks  in  their  high 
places.  But  it  is  to  inanimate  nature  that  we 
must  go  for  our  most  brilliant  examples  of  phys- 
ical force.  What  power  in  the  wind,  when,  as  a 
tornado,  it  sweeps  along  at  more  than  one  hun- 
dred miles  an  hour ;  demolishing  mansions,  up- 
rooting forests,  and  lifting  ponderous  ships  far  in- 
land on  their  eddies  !  What  power  in  the  ocean- 
swell  as  it  tosses  an  entire  navy  to  the  skies  witli 
apparently  as  much  ease  as  if  it  were  a  single 
cockle-shell !  —  What  is  this  that  comes  rushing 
through  the  landscape  with  smoky  breath  and 
thunderous  step,  dragging  thousands  of  tons  at 
the  pace  of  winds  ?  Within  that  flying  iron  cra- 
ter is  imprisoned  one  of  nature's  brawniest  forces, 
steam — throwing  off  feats  of  toil  with  its  vaporous 
arms,  which  arms  of  flesh  and  blood  have  never 
even  been  fabled  to  do.  —  What  have  we  here  ?  A 
few  barrels  filled  with  very  simple  black  grains. 
One  has  but  to  drop  a  spark  among  them  to  wit- 
ness a  sudden  development  of  power  that  shall 


POWER   OF  NATURE.  179 

deafen  earth  and  heaven  with  its  voice,  and  lift  a 
city  into  raid-air. — Would  you  see  a  mightier 
energy  still  ?  It  is  the  year  1755.  An  unwonted 
trembling  stirs  the  air  and  ground  of  Lisbon.  In 
a  few  moments  the  broad  city  is  in  heaps.  The 
plain  around  runs  in  waves,  like  the  sea  when 
lashed  by  a  tempest.  See  —  the  distant  moun- 
tain-ranges themselves  impetuously  shake  and 
rend  and  topple  ;  Europe,  to  the  Highlands  of 
Scotland,  heaves  ;  heaves  Africa  ;  heaves  the 
whole  broad  Atlantic,  with  all  its  huge  gravi- 
ties, from  the  Pillars  of  Hercules  to  the  New 
World !  When  oceans  and  continents  are  so 
tossed  and  shot  aloft,  what  stalwart  shoulders  of 
gas  and  steam  and  fire  are  heaving  at  the  mighty 
burden !  Other  forces  among  us  are  not  small ;  but 
this  of  the  earthquake  is  easy  king  over  all  these 
terrestrial  children  of  pride.  Terrestrial,  I  say  : 
but  there  are  forces  not  terrestrial  which  are  of  a 
still  huger  and  loftier  pattern  —  celestial  forces, 
to  which  those  of  our  earth  are  what  the  bubble- 
globules  of  the  children  are  to  the  globed  worlds 
of  space.  When  such  a  planet  as  Jupiter  is 
moving  at  the  rate  of  some  thirty  thousand  miles 
an  hour  ;  when  such  a  sun  as  ours  is  moving  at 
the  rate  of  some  three  thousand  miles  a  minute  ; 
when  such  a  nebula  as  our  Milky  Way,  with  its 
eighteen  millions  of  suns,  goes  wheeling  at  the 
same  average  speed  about  its  center  of  gravity 
—  there  is  a  momentum  for  you,  a  magazine 


180  SIXTH  LECTURE. 

of  force  by  the  side  of  which  earthquakes  are 
puny,  and  all  the  stormy  winds  that  ever  blus- 
tered and  fought  in  their  fabled  caves  mere  zeros ! 
Some  say  that  there  is  but  one  forcer  in  all  nature 
—  none  perhaps  more  apt  to  say  it  than  the 
rejecters  of  the  supernatural  —  that  the  forces 
which  pump  and  assimilate  and  reject  in  every 
blade  of  grass  and  leaf  and  animal  fiber ;  the 
forces  that  throb  in  every  ray  of  light  and  heat 
and  electricity  and  magnetism,  the  forces  that 
swell  and  toil  in  every  atom  of  matter,  the  me- 
chanical forces,  the  chemical  forces,  the  spiritual 
forces,  the  forces  here  and  the  forces  yonder  to 
the  universe's  last  suburb  —  that  all  these  forces, 
with  their  incomprehensible  sum-total  of  simul- 
taneous impulses,  are,  after  all,  but  branches  of 
one  great  central  force  pushing  outward  in  an  in- 
finite variety  of  directions  and  forms.  If  this  is 
so  —  and  who  is  competent  to  positively  deny  it  — 
what  a  single  force  that  is  which  can  diffuse  itself 
over  so  immense  an  area,  and  divide  itself  so  in- 
finitely, and  yet  thunder  away  at  special  points 
with  such  marvelous  and  terrible  energy  !  If 
this  is  not  so,  still  what  a  wondrous  hive  of 
swarming  and  independent  dynamics  in  this  wide 
nature  of  ours  ! 

Of  course,  no  one  could  have  the  hardihood  to 
say  that  a  nature  stocked  with  such  energies  as 
these  makes  positively  against  the  doctrine  of  a 
Creator  who  is  himself  an  Almighty  Force.  On 


POWER   OF  NATURE.  181 

the  contrary,  there  is  a  friendly  harmony  between 
the  doctrine  and  the  fact.  Were  we  to  find  in 
actual  existence  a  Personal  Power  to  whom  noth- 
ing is  impossible,  and  learn  that  he  is  about  to 
produce  a  universe,  we  should  expect  to  see  pro- 
duced just  such  a  wonderfully  strong  nature  as  we 
actually  have  —  a  nature  peopled  with  strengths, 
momenta,  brawny  agencies  of  most  imposing  forms 
and  magnitudes.  A  weak  system,  a  system  that 
is  puny  in  its  operations  and  trifling  in  its  effects, 
would  misrepresent  him  —  shall  I  not  say,  would 
be  unworthy  of  him  ?  Most  persons  would  cer- 
tainly call  it  unsuitable ;  would  say  that  his 
very  nature  as  an  Infinite  Power  would  demand 
of  him  that  he  should  produce  a  system  that 
would  be  continually  turning  out  the  greatest  re- 
sults, and  so  must  include  forces  of  the  greatest 
efficiency.  When,  then,  I  am  told  that  a  Sublime 
Force,  who  has  Almighty  for  his  name,  is  the  au- 
thor of  nature  ;  and  I  then  proceed  to  place  my- 
self out  under  the  open  dome  amid  the  pulsings 
and  tossings  of  innumerable  and  sometimes  im- 
measurable momenta,  and  so  lay  myself  honestly 
open  to  all  their  subtle  hints  and  magnetisms;  I 
feel  myself  silently  drinking  in  predispositions  to 
faith  as  the  exposed  fleece  drinks  in  the  dew  —  I 
feel  that  the  doctrine  matches  facts ;  that  the  as- 
serted creator  and  creation  fit  each  other  as  do 
the  die  and  the  face  of  the  coin  which  it  has 
stamped ;  that  the  theory  has  at  least  the  bene- 


182  SIXTH  LECTURE. 

diction  of  yet  another  verisimilitude  and  presump- 
tion ;  that  Nature,  instead  of  making  oath  with  se- 
rene brow  and  uplifted  hand,  that  there  is  no  won- 
drous God,  significantly  asks,  with  abashed  voice, 
"  Is  there  not  such  a  Being  ?  "  —  in  fine,  I  feel 
that,  as  the  veil  continues  to  rise  from  the  face  of 
the  painting,  it  reveals  still  another  characteristic 
of  the  Great  Master,  clears  up  another  stretch  of 
that  vista  which  conducts  the  sight  toward  Titian 
bending  over  his  canvas  —  the  fifth  of  those  sever- 
al harmonies  which,  as  successively  presented, 
warrant  us  in  looking  faith  ward  with  ever-grow- 
ing kindliness  of  aspect. 

Another  feature  of  Nature  is  its  remarkable  re- 
lation to  law. 

Notice  law  and  its  exceptions  —  the  general 
steadfastness  of  modes  of  being  and  action  in  na- 
ture, and  the  occasional  breaches  in  that  stead- 
fastness. 

On  the  earth's  surface,  in  its  dark  interior,  in 
the  air  and  vault  above,  in  the  instant  present  and 
the  ancient  past  —  everywhere,  law  waves  its 
mighty  scepter.  Atoms  and  masses,  the  ponder- 
ables and  inponderables,  the  organic  and  inor- 
ganic, the  living  and  dead  —  all  are  evidently 
subjected  in  their  modes  of  being  and  action  to 
certain  fixed  rules,  sometimes  particular,  but 
more  often  covering  whole  classes  of  objects. 
Not  a  particle  floats  at  random  or  as  a  unit :  not 
a  leaf  grows  or  falls  save  according  to  rigid  gene- 


RELATION  TO  LAW.  •  183 

ral  principles  of  science.  All  chemical  elements 
have  their  modes  and  measures  of  combination  to 
which  they  steadfastly  adhere.  All  heat,  electri- 
city, magnetism,  gravity,  act  according  to  abiding 
methods  which  philosophers  have  gradually  dis- 
covered and  arranged  into  the  sciences  of  natural 
philosophy.  The  great  processes  of  vegetable  and 
animal  life  proceed  after  the  same  forms  and  steps, 
from  age  to  age.  The  stone  beds  of  the  world  are 
formed  and  modified  in  certain  set  ways  which 
are  the  same  now  as  in  the  periods  anterior  to 
man.  Even  the  weather,  so  often  called  fickle, 
has  its  stable  methods ;  almost  every  year  bring- 
ing to  light  some  new  general  fact  in  meteorology, 
or  extending  the  application  of  an  old  one.  Day 
and  night  succeed  each  other,  every  twenty-four 
hours,  without  variation.  The  seasons  do  not 
change  their  order  or  general  character.  All  of 
Kepler's  and  Newton's  laws  are  as  operative  to- 
day as  they  ever  have  been  since  their  discovery. 
The  planets  shoot  round  the  sun  and  are  circled 
by  their  own  moons,  on  substantially  the  same 
elliptical  orbits,  in  the  same  times,  and  with  the 
same  principles  of  alternate  retardation  and  accel- 
eration  as  of  old.  All  known  changes  in  the  plan- 
etary orbits  have  been  found  to  be  bound  in  a 
law  of  periodicity  which  is  apparently  invariable. 
So  beyond  the  solar  system.  Law  still ;  nothing 
but  law ;  law  everywhere  on  ten  thousand  bla- 
zing thrones ;  largely  the  same  laws  that  prevail 


184  SIXTH  LECTURE. 

in  our  own  system  !  As  far  as  we  can  observe  — 
and  it  is  no  little  that  has  been  observed  —  those 
distant  orbs  reverence  the  various  principles  of 
gravitation  and  mechanics,  and  keep  as  rigidly  to 
their  behests,  as  when  the  earliest  astronomy  gazed 
at  them  from  its  rude  Uraniberg  of  a  hill-top. 
And  every  man  of  science  is  well  persuaded  that, 
could  his  observation  alight  on  particular  orbs  of 
those  remote  and  twinkling  hosts,  he  would  find 
their  minutest  details  bound  up  in  the  chains  of 
the  same  adamantine  regularity  that  rules  our 
own  globe. 

So  in  general  we  speak.  But  we  must  not  be 
understood  to  speak  with  absolute  precision  of 
language.  In  this  wide  scene  of  steadfast  ar- 
rangements, there  are  outbreaks  of  anomaly  — 
ruptures  and  rents  and  dislocations  in  the  habits 
and  ongoings  of  nature,  like  those  in  the  strata 
of  the  earth.  It  is  a  settled  law  of  nature  that 
like  shall  produce  like  ;  yet  from  perfect  animals 
and  vegetables  occur  occasional  monstrosities  of 
organization.  It  is  a  settled  course  of  nature 
that  certain  substances,  called  poisons,  if  freely 
introduced  into  animal  systems,  destroy  life  ;  yet 
now  and  then  a  man  is  found  who  is  even  nour- 
ished by  these  agents  of  destruction.  It  is  a  fixed 
mode  of  nature  that  frost  withers  flat  foliage  ;  yet 
the  flat  leaves  of  the  wild  laurel  flourish  out  our 
"hardest  winters.  It  is  a  fixed  way  of  nature  that 
the  heavenly  bodies  move  in  ellipses  ;  yot  there 


RELATION   TO  LAW.  185 

is  reason  to  believe  that  some  comets  have  been 
found  moving  on  the  curve  called  a  parabola. 
The  steadfast  habit  of  nature  is  against  a  general 
planetary  deluge,  or  conflagration,  or  glacier- 
period,  or  destructive  convulsion  ;  yet  such  disas- 
ters, if  geology  may  be  trusted,  have  several  times 
occurred,  at  immense  intervals,  in  the  history  of 
our  own  planet.  Great  exceptional  events ; 
phenomena  without  fellows  through  an  astonish- 
ing stretch  of  ages ;  what  have  the  appearance 
of  broad  fractures  and  dislocations  of  nature, 
though  in  reality  they  may  be  the  rare  resultants 
and  accumulations  of  innumerable  natural  forces 
and  laws  crossing  each  other  in  all  directions  ; 
the  entire  destruction  and  rehabilitation  of  animal 
and  vegetable  species  —  such  events  have  taken 
place  on  this  globe  again  and  again.  Repeatedly 
has  the  earth  been  drowned  and  torn  in  pieces. 
It  has  been  piled  with  snow  and  ice  from  pole  to 
pole.  It  has  been  all  ablaze  and  fused.  And  is 
it  not  on  the  idea  of  such  a  conflagration  that  we 
can  best  account  for  the  new  stars  that  have  some- 
times flashed  suddenly  on  the  sight  with  all  the 
splendor  of  Yenus  at  its  brightest,  and,  after  a 
few  months  of  changing  color  and  gradual  decay, 
finally  disappeared  ?  Thus  in  the  bosom  of  a 
general  steadfastness  are  found  occasional  out- 
breaks of  anomaly.  It  is  as  among  the  geologic 
strata  —  where  are  found  faults,  dislocations,  fis- 
sures, and  even  reversions  of  those  great  rock- 


186  SIXTH  LECTURE. 

beds  which  in  general  are  laid  down  on  a  plan  of 
utmost  regularity.  The  course  of  nature  is  like 
some  great  thoroughfare,  which  advances  through 
great  distances  without  the  slightest  solution  of 
its  continuity,  but  at  last  finds  a  great  river  thrust 
squarely  across  its  track.  On  this  side  the  thor- 
oughfare, on  that  side  the  thoroughfare,  and  here 
the  broad,  deep  flow  of  the  bridgeless  river  — 
a  river  worth  to  the  public,  it  may  be,  many 
times  what  the  perfect  continuity  of  the  road 
would  be. 

Now  this  much  is  certain.  No  one  can  say  that 
this  characteristic  of  nature  makes  positively 
against  such  a  steadfast  and  yet  miracle-working 
God  as  is  affirmed  in  the  Christian  Scriptures. 
Instead  of  opposition,  there  is  positive  harmony 
between  the  fact  and  the  doctrine.  Indeed,  such 
a  nature  as  is  observed  is  just  what  one  would 
have  expected  to  come  from  such  a  Creator  as  is 
taught.  Nay,  as  general  laws  are  necessary  to 
make  science  possible,  to  enable  men  to  forecast 
and  profit  by  experience,  to  serve  as  a  basis  for  all 
comprehensive  business  and  for  all  civil  govern- 
ment —  as  the  broader  and  profounder  the  intel- 
ligence, the  more  it  is  pleased  with  and  tends  to 
work  by  general  principles,  we  may  say  that  the 
very  nature  and  circumstances  of  Deity  would  de- 
mand of  him,  in  case  he  should  create,  to  create  a 
generally  steadfast,  law-abiding  universe.  At  the 
same  time,  a  miracle-worker  —  one  who  sees  acer- 


RELATION  TO  LAW.  187 

tain  essential  imperfection  and  intractability  in 
seco  id  causes,  preventing  their  matching  on  all 
occasions  the  perfection  of  his  ideas  ;  who,  more- 
over, sees  it  undesirable  to  allow  mere  nature  to 
hide  its  Maker  altogether  behind  its  swarming 
screen,  and  give  to  the  ideas  of  necessity  and  fatal- 
ity full  sweep  in  human  minds  —  I  say,  such  a 
baing  would  be  under  a  loud  call  to  provide  in  the 
constitution  arid  course  of  nature  such  sugges- 
tions and  prophecies  of  miracles  as  would  gradu- 
ally, though  perhaps  unconsciously  to  them,  pre- 
pare the  minds  of  men  for  those  crowning 
abnorinals  of  the  system.  He  must  have  the 
glory  of  his  personal  agency  glimmer  through 
occasional  rents  in  the  uniformity  of  nature. 
An  anomaly-sprinkled,  miracle-suggesting,  as  well 
as  stable,  universe  must  proceed  from  his  won- 
drous hand.  He  would  be  in  conflict  with 
himself  were  he  to  produce  any  other.  And 
when  I  am  told  of  one  who  is  actually  just 
this  sort  of  divinity  —  both  law  and  miracle  : 
both  giver  and  keeper  to  an  almost  infinite 
extent  of  moral  laws  which  shall  not  pass  away ; 
while  his  iron  will,  throned  as  supremely  in 
the  realm  of  matter  as  of  morals,  yet  launches 
forth  into  special  providences  and  miracles  on 
extraordinary  occasions  —  when  I  am  told  of 
him,  and  I  then  place  myself  out  under  the 
open  dome  amid  the  massive  but  occasionally 
rifted  uniformities,  and  open  myself  freely  to  all 


188  SIXTH  LECTURE. 

their  subtle  hints  and  magnetisms,  I  feel  myself 
softly  drinking  in  predispositions  to  faith,  as  the 
exposed  fleece  drinks  in  the  dew.  I  feel  that  the 
doctrine  and  the  facts  are  at  one  ;  that  the  asserted 
Creator  and  the  observed  creation  fit  each  other 
as  do  the  signet  and  the  seal  just  stamped  ;  that 
another  verisimilitude  spreads  blessing,  if  trem- 
ulous, hand  over  the  theory ;  that  Nature  in- 
stead of  sonorously  swearing  that  there  is  no 
Divine  Being  whose  double  name  is  Law  and  Mira- 
cle, significantly  asks,  with  abashed  and  startled 
tones,  "  Is  there  not  such  a  Being  ?  "  In  fine,  I 
feel  that,  as  the  veil  continues  to  rise  from  the  face 
of  the  painting,  it  reveals  still  another  character- 
istic of  the  Great  Master,  clears  up  another  stretch 
of  that  vista  which  conducts  the  sight  toward 
Titian  bending  over  his  canvas  —  the  sixth  of 
those  several  harmonies  which,  as  successively  pre- 
sented, warrant  us  in  looking  faithward  with  ever- 
growing kindliness  of  aspect. 

Another  feature  of  Nature  is  its  wonderful  re- 
lation to  time  and  motion. 

How  long  has  our  race  existed  ?  The  infidel 
may  choose  to  say  a  hundred  thousand  years  ; 
none  will  say  less  than  six  thousand.  How  long 
has  the  earth  itself  existed  ?  The  atheist  may 
choose  to  say,  Forever.  The  geologist,  thinking 
of  his  coal  beds  and  deltas  and  rocky  strata  sown 
with  the  bones  of  extinct  species,  and  of  the  time 
requisite  for  their  formation,  is  sure  of  several 


RELATION  TO   TIME  AND  MOTION.          189 

hundred  thousand  years.  How  long  are  the 
earth  and  its  confederates  in  the  solar  system 
calculated  to  endure  ?  Geometry  declares  that 
no  element  of  decay  within  endangers  the  sta- 
bility of  the  system  of  the  world.  That  year 
which  circumscribes  our  seasons  is  only  three 
hundred  and  sixty-five  days  ;  but  the  earth  has 
another  year  to  which  this  is  a  mere  point  —  its 
pole  goes  nodding  through  space  in  a  circle  which 
it  takes  twenty-five  thousand  years  to  traverse. 
What  think  you  of  a  planet  whose  winter  is  more 
than  forty  of  our  years,  of  a  comet  whose  year  is 
more  than  thirty  of  our  centuries,  of  a  sun  whose 
year  is  more  than  eighteen  thousand  of  our  mil- 
lenniums? All  the  planetary  orbits  pass  through 
cycles  of  changes  varying  in  length  from  a  few 
centuries  to  nine  thousand,  to  seventy  thousand, 
to  even  many  million  years  ;  but  the  greatest  of 
these  planetary  cycles  are  as  nothing  compared 
with  those  enormous  periods  which  bound  the 
perturbations  and  express  the  secular  equations 
of  the  sun  and  fixed  stars  —  periods  including 
more  years  than  imagination  has  ever  succeeded 
in  realizing  to  itself.  What  amazing  longevities! 
What  portentous  numerals!  They  are  hiero- 
glyphics of  the  everlasting.  They  lift  us  among 
the  dizziest  peaks  of  the  sublime. 

These  immense  periods,  interspersed  with  others 
exceedingly  small,  sometimes  express  an  exceed- 
ingly slow  movement  among  the  powers  of  nature. 


190  SIXTH  LECTURE. 

In  other  cases,  the  movement  with  which  they 
are  connected  is  exceedingly  rapid.  The  times 
consumed  in  the  formation  of  the  coal-beds  and 
rock-strata,  and  in  the  long  perturbations  of  the 
planetary  and  stellar  orbits,  are  examples  of  the 
first  class  of  periods  ;  the  years  of  the  planets  and 
stars  in  their  orbits  are  examples  of  the  second. 
In  the  first  class,  natural  forces  creep  along  to 
their  objects  with  miraculous  slowness  ;  in  the 
other,  they  flash  along  with  swiftness  equally 
astounding.  Some  orbits  gradually  lengthen 
themselves,  say  an  inch  in  a  thousand  years. 
Some  of  the  stars  dart  along  their  year  of  one 
hundred  and  eighty  thousand  centuries  at  the  in- 
comprehensible rate  of  one  hundred  and  eighty 
thousand  miles  an  hour.  Could  we  plant  our- 
selves immovably  at  a  certain  point  in  the  celes- 
tial spaces,  and  see  our  sun  go  sailing  by  with  all 
its  glorious  squadrons  of  planets  and  moons  — 
sailing  down  the  abyss  as  if  driven  by  ten  thou- 
sand hurricanes  —  would  not  the  sight  of  such 
celerity  almost  irrecoverably  daze  both  senses  and 
spirit  ? 

If,  now,  one  should  start  up  to  say  that  these 
great  cycles,  imbosoming  unutterable  extremes 
of  movement,  makes  positively  against  an  Eter- 
nal God  who  is  able  to  move  to  his  purpose  like 
the  light  or  at  a  rate  so  trifling  as  to  be  quite  im- 
perceptible by  human  senses,  we  should  laugh  his 
logic  to  scorn.  We  know  better.  These  are  facts 


RELATION  TO   TIME  AND  MOTION.          191 

that  palpably  agree  with  such  a  theism.     Instead 
of  contradicting  it,  they  express  a  state  of  things 
that  might  have  been  expected  from  a  being  who 
has  both  unlimited  time  and  unlimited  speed  at 
his   disposal  —  who,  if  he   chooses   to  wait,  has 
never  occasion  to  haste  ;  or,  if  he  chooses  to  haste, 
has  never  occasion  to  wait  —  who  is  alike  able  to 
dart  on  his  purpose  as  if  infinite  whirlwinds  were  in 
his  wings,  or  to  approach  it  at  a  rate  so  minute  that 
no  human  sense  can  discern  the  movement  in  the 
lapse  of  generations.     Suppose  such  a  God  to  be 
about  to  create  a  nature,  could  you  not  confidently 
predict  after  this  manner — "  This  Being  of  mighty 
periods  will  establish  mighty  periods :  this  Being 
who  can  readily  proceed  on  his  endlessly  varied  de- 
signs, at  all  imaginable  and  unimaginable  rates  of 
speed,  will  diversify  his  works  with  all  the  veloci- 
ties." A  God  who  himself  has  no  duration  to  speak 
of —  if  there  may  be  such  a  God  —  would  never 
have  stored  his  nature  with  such  mighty  cycles;  a 
God  who  himself  never  did  a  swift  thing  would 
never  have  set  his  laws  to  spurring  on  planets  and 
suns  so  astoundingly ;  a  God  who  himself  never 
did  a  slow  thing  would  never  have  yoked  such 
slow-footed  forces  to  events,  as  we  observe  actually 
dragging  at  some  of  them.     It  is  only  a  God  who 
has  substantial  forevers  on  his  hands,  and  who  on 
occasion  can  lighten  and  on  occasion  can  linger 
ineffably  along  the  highway  of  his  purposes,  who 
is  properly  represented  by  such  a  nature.     In  case 


192  SIXTH  LECTURE. 

he  gives  any  nature  at  all,  his  character  demands 
of  him  to  give  just  this  —  one  expressing  his  own 
attributes.  So  when  I  am  told  of  one  whose  lon- 
gevity is  eternity,  whose  orbit  of  existence  has  an 
infinite  axis,  who  reaches  an  Atonement  after 
slowly  beating  toward  it  for  forty  centuries,  who 
is  ages  and  dispensations  in  establishing  his  king- 
dom in  the  world,  who  commonly  approaches  the 
punishment  of  sinners  with  steps  lingering  through 
numberless  delays  and  forbearances,  and  who  yet 
sometimes  yokes  steeds  of  wind  and  fire  and  foam 
to  his  car  —  as  when  some  Korah  and  his  com- 
pany go  down  quick  into  the  pit ;  or  some  Uzziah, 
profanely  grasping  an  ark,  falls  dead  ;  or  some 
Ananias  and  Sapphira,  lying  to  the  Holy  Ghost,  are 
rushed  to  judgment  in  an  instant's  brief  space  — 
when  I  am  told  of  such  a  God  creating  nature  ; 
and  I  then  betake  myself  abroad  under  the  open 
dome  amid  those  swarming  and  wondrous  orbits 
of  time,  now  scarrefl  and  smoking  with  the  hot 
hoofs  of  electric  forces,  and  now  pressed  by  the 
velvety  and  trackless  feet  of  forces  born  of  the 
snail ;  and  frankly  lay  myself  open  to  all  their 
subtle  hints  and  magnetisms  —  I  feel  myself  silent- 
ly drinking  in  faith,  as  the  exposed  fleece  drinks 
in  the  dew  —  I  feel  that  there  is  a  significant 
matching  of  what  we  are  taught  with  what  we 
observe  ;  that  such  theism  is  on  most  excellent  and 
embracing  terms  with  Nature,  which,  so  far  from 
saying  with  uplifted,  oath-making  hand,  '  that 


MYSTEEIOU8NESS  OF  NATURE.  193 

there  is  no  Eternal  God  who,  as  an  agent,  is  equally 
at  home  in  an  instant  and  an  age,'  at  least  stands 
tremulously  querying,  "  Is  there  not  such  a  Be- 
ing ?  " —  in  fine,  I  feel  that,  as  the  veil  continues  to 
rise  from  the  face  of  the  painting,  it  reveals  still 
another  characteristic  of  the  Great  Master,  clears 
up  another  stretch  of  that  vista  which  conducts 
the  sight  on  Titian  painting  away  sublimely  at  his 
glowing  and  glorified  landscape  —  the  seventh  of 
those  several  harmonies  which,  as  successively 
presented,  warrant  us  in  looking  faithward  with 
ever-growing  kindliness  of  aspect. 

Another  feature  —  the  mysteriousness  of  Na- 
ture. 

Who  does  not  know  it  ?  —  terrestrial  nature 
is  one  huge  sphinx.  She  vomits  enigmas  on  us 
in  seas.  Riddles  too  profound  for  the  highest 
science  yet  in  our  possession  lurk  in  every  ray 
of  light,  in  every  blade  of  grass,  in  every  rudest 
stone.  Only  some  of  the  coarser  facts  in  rela- 
tian  to  a  few  things  here  and  there,  have  been 
picked  up  and  systematized ;  and  these  are  what 
compose  our  boasted  sciences.  From  surface  to 
center,  the  earth  is  choked  with  mysteries  whose 
stony  rind  has  never  yet  received  a  blow,  much 
less  a  fracture,  from  the  mallet  of  investigation. 
Come  now,  ye  great  Computers,  compute  for  us 
how  long  it  will  be  before  the  science,  which  loses 
itself  at  the  very  threshold  of  the  complexities 
of  this  world,  will  be  able  to  swoop  down  with 

13 


194  SIXTH  LECT^  HE. 

triumphant  wing  upon  the  surfaces  and  to  the 
fiery  centers  of  those  fellow  planets  that  myste- 
riously weave  and  interweave  paths  across  the 
concave,  and  thoroughly  solve  the  problem  of  all 
their  swarming  contents !  A  disorderly  maze 
are  the  apparent  paths  of  the  members  of  our 
solar  system !  But  you  say  that  the  real  paths 
are  not  as  intricate  as  the  apparent.  Take  your 
stand,  then,  at  the  sun,  and  observe  planets  and 
comets  going  and  coming  at  all  distances  and 
rates  of  velocity  and  directions ;  while  around 
most  of  the  larger  planets  are  similarly  moving, 
other  systems  of  satellites  —  is  it  not  an  intricate 
as  well  as  a  brave  sight  ?  Can  you  see  through 
the  mazy  plan  ?  But  you  say  that  it  has  been 
seen  through,  and  planetariums  have  been  made 
that  clearly  represent  the  whole  thing  to  us  with- 
in a  few  feet  of  space.  How  many  centuries 
and  philosophers,  0  Copernicus  —  Copernicus,  I 
say,  away  yonder  in  the  depths  of  four  hundred 
years  ago  —  did  it  take  to  make  that  orrery  and 
solve  that  riddle  of  the  system  of  the  world  ? 
Indeed,  it  is  yet  very  far  from  solution.  Astron- 
omers can  only  completely  account  for  the  move- 
ments of  a  system  of  two  bodies.  A  system  of 
three  is  quite  beyond  them ;  one  of  a  hundred 
and  more  bodies,  like  our  solar  system,  immeasur- 
ably beyond  them.  There  is  not  even  a  hope 
that  science,  with  all  its  dynamical  calculuses, 
will  ever  overtake  this  higher  problem.  But 


MYSTERIOUSNESS  OF  NATURE.  195 

there  is  a  higher  problem  still.  Solar  system 
revolves  around  solar  system;  a  group  of  such 
systems  around  a  similar  group ;  a  cluster  of 
such  groups  around  a  similar  cluster;  a  firma- 
ment of  such  clusters  around  a  similar  firmament. 
Indeed,  as  we  have  seen,  the  whole  universe  of 
stars,  with  all  the  countless  fleets  of  planets  and 
moons  which  they  represent,  must,  according  to 
the  law  of  gravity,  revolve  about  a  last  center  of 
centers.  Let  us  go  to  it.  Standing  at  this 
Heaven  —  for  is  not  this  the  dazzling  metropolis 
where  dwells  the  sublime  Cesar  of  the  creation — 
standing  at  this  wondrous  point,  and  looking 
forth  on  the  countless  nebulas  coming  and  going 
at  all  imaginable  distances,  speeds,  and  direc- 
tions—  Id,  what  a  glorious  scene  of  bewilder- 
ment and  unsearchable  complexity !  It  fairly 
takes  away  our  breath  to  look.  There  is  no 
more  spirit  left  in  us.  If  a  system  of  three 
bodies  is  too  much  for  the  most  subtle  and  com- 
prehensive science  yet  known,  what  can  ever  be 
done  by  all  coming  generations  and  geniuses, 
however  imperial,  toward  mastering  such  laby- 
rinthian  immensity  of  involved  orbs  ? 

Now  hearken  to  the  Christian  Scriptures  — 
affirming  a  Maker  of  nature  who  is  himself  the 
mightiest  of  all  enigmas.  "  Verily,  thou  art  a 
God  that  hidest  thyself — Canst  thou  by  searching 
find  out  God;  canst  thou  find  out  the  Almighty 
to  perfection  —  It  is  high  as  heaven  ;  what  canst 


196  SIXTH  LECTURE. 

thou  do :  deep  as  hell ;  what  canst  thou  know  ?  " 
Does  the  aspect  of  nature  contradict  this  doc- 
trine ?  Who  will  presume  to  deny  that  the  in- 
comprehensible materialism  about  us,  to  say 
nothing  of  the  more  incomprehensible  spiritual- 
ism within  us,  is  just  what  one  would  expect  to 
find  issuing  from  the  hands  of  an  incomprehensi- 
ble Creator  —  a  being  mysteriously  without  a 
beginning,  mysteriously  self-existent,  mysteriously 
able  to  make  the  greatest  and  noblest  things  out 
of  nothing  by  simple  volition,  mysteriously  all- 
knowing,  mysteriously  unfettered  in  the  appli- 
cation of  his  power  and  knowledge  by  all  con- 
ditions of  space  and  duration  and  personal 
presence,  .mysteriously  Three  in  One  —  in  short, 
a  being  enveloped  in  a  terrible  pomp  and  majesty 
of  sunset-clouds,  whose  broken  lines  never  per- 
mit the  orb  that  glorifies  them  to  appear,  even 
for  a  moment,  in  clear  and  golden  contour  on 
our  rapt  sight.  Such  a  being,  setting  out  to 
create,  would  be  likely  to  give  us  the  present 
enigmatic  universe,  nay  —  for  why  state  the  mat- 
ter so  feebly  —  would  be  sure  to  give  it.  Like 
every  other  copious  author,  he  would  reproduce 
his  own  traits.  An  unutterable  sphinx  himself, 
his  creatures  would  be  sphinxes.  A  nature  from 
the  hands  of  God  that  I  can  comprehend,  or 
make  any  approach  to  comprehending  —  prepos- 
terous! A  creation  that  to  me,  with  my  low 
place  and  filmy  vision  and  narrow  orbit,  is  not 


MTSTERIOUSNESS  OF  NATURE. 

steeped  in  seas  of  mystery  —  preposterous  !  If  a 
Jehovah  build  the  temple  of  nature  at  all,  he  will 
found  it  on  mysteries,  frame  it  with  mysteries, 
cover  and  dome  it  with  mysteries,  pillar  and 
ballast  it  with  mysteries,  pave  and  ceil  it  with 
a  mosaic  of  mysteries  —  surely  he  will.  And 
when  I  am  told  of  a  being  whose  own  nature  is 
an  overwhelming  problem  ;  whose  attributes  have 
no  horizon,  no  zenith,  and  no  nadir ;  whose  ends 
respect  all  possible  objects  and  interests,  and 
spread  themselves  out  in  plans  of  boundless  \  ast- 
ness  whose  merest  corners  and  differentials  only 
are  visible  to  men  of  the  widest  scope :  when  I 
am  told  of  him,  and  I  then  place  myself  out  un- 
der nature's  open  dome,  amid  its  Protean  inscru- 
tableness  of  leaf  and  star,  of  whole  crowded  earth 
and  circumventing  heavens  —  the  peopled  heavens 
where  sweep  in  inextricable  maze  the  hurricane 
hosts  of  advancing  and  retreating  orbs  ;  and  open 
my  soul  candidly  to  all  their  silent  suggestions 
and  magnetisms  —  I  feel  myself  drinking  in  faith, 
as  the  fleece  spread  out  under  the  stars  drinks  in 
the  dew  —  I  feel  that  the  facts  give  embracing 
arms  to  the  doctrine  ;  that  the  actual  universe, 
instead  of  swearing  with  decisive  voice  and  hand 
uplift  to  heaven  that  there  is  no  inscrutable  God, 
significantly  asks  with  panting  whisper  and  color 
that  conies  and  goes, "  Is  there  not  such  a  Being  ?  " 
In  fine,  I  feel  that  our  continued  lifting  of  the 
veil  from  the  painting  has  disclosed  another  char- 


198  SIXTH  LECTURE. 

acteristic  of  the  great  master  to  whom  the  work 
is  attributed ;  has  cleared  up  another  stretch  of 
that  vista  which  conducts  the  sight  to  Titian  in 
the  act  of  glorifying  his  canvas  into  the  Milanese 
Coronation-Christ  —  another  of  those  many  har- 
monies which,  as  successively  presented,  warrant 
us  in  looking  faithward  with  ever-growing  kindli- 
ness of  aspect. 


14  DAY  USE 

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